CN1237654C - Two-port isolators and communicators - Google Patents

Abstract

Provided is a two-port isolator capable of adjusting insertion loss characteristics and isolation characteristics, and to provide a communication apparatus. The two-port isolator 1 is roughly provided with a metallic case consisting of a metallic upper case 4 and a metallic lower case 8; a permanent magnet 9; a central electrode assembly 13 consisting of a ferrite 20 and central electrodes 21, 22; and a laminated substrate 30. In the assembly 13, two pairs of first and second central electrodes 21, 22 are provided on the top surface of the circular microwave ferrite 20 so that the electrode 21 orthogonally crosses the electrode 22 at right angles with an insulating layer intervening. The electrode width of the electrode 21 is different from that of the electrode 22. With this constitution, an inductance L1 of the electrode 21 differs from an inductance L2 of the electrode 22.

Description

Two-port isolators and communicators

technical field

The invention relates to a two-port isolator, in particular to a two-port isolator and a communication device used in microwave bands.

Background technique

Isolators generally have the function of allowing signals to pass only in the transmission direction and blocking the reverse transmission, and are used in the transmission circuit of mobile communication devices such as car phones and mobile phones.

For example, as such an isolator, a two-port type isolator (an isolator having two center electrodes of a first center electrode and a second center electrode) has been conventionally known. This two-port type isolator accommodates a permanent magnet, a ferrite, and a first center electrode and a second center electrode arranged on the main surface of the ferrite in a metal case formed by joining a metal lower case and a metal upper case. , two matching capacitors and resistors. Usually, the shape of the first center electrode and the second center electrode are the same, and the capacitances of the two matching capacitors are also the same.

The insertion loss characteristics and isolation characteristics required for two-port isolators used in mobile communication equipment are determined in conjunction with the communication system. Therefore, when comparing the insertion loss characteristics and isolation characteristics of an actual two-port type isolator with the required specifications of a communication system, there may be cases where the insertion loss characteristics do not meet the required specifications although the isolation characteristics are sufficient to meet the required specifications. Conversely, the insertion loss characteristic is sufficient to meet the required specification, but the isolation characteristic cannot meet the required specification.

On the other hand, in mobile communication equipment, in order to reduce the power consumption of the transmission circuit and increase the continuous call time, it is strongly desired to reduce the insertion loss even if the isolation characteristics are slightly deteriorated. However, the prior art has no means to satisfy this desire, and cannot adjust the insertion loss characteristics and isolation characteristics of the two-port type isolator.

Therefore, an object of the present invention is to provide a two-port type isolator and a communication device capable of adjusting insertion loss characteristics and isolation characteristics.

Contents of the invention

In order to achieve the above object, the two-port isolator of the present invention comprises

(a) Permanent magnets,

(b) Ferrite to which a DC magnetic field is applied by a permanent magnet,

(c) a first central electrode arranged on the main surface or inside of the ferrite and one end electrically connected to the first input and output port and the other end electrically connected to the second input and output port,

(d) a second central electrode that is electrically insulated from the first central electrode and is arranged on the main surface or inside of the ferrite and that has one end electrically connected to the second input-output port and the other end electrically connected to the third port,

(e) a first matching capacitor electrically connected between the first input and output port and the second input and output port,

(f) a resistor electrically connected between the first input-output port and the second input-output port, and

(g) a second matching capacitor electrically connected between the second input and output port and the third port,

(h) The third port is electrically grounded, and the inductance L1 of the first center electrode is different from the inductance L2 of the second center electrode.

In addition, the two-port type isolator of the present invention includes

(i) permanent magnets,

(j) Ferrite to which a DC magnetic field is applied by a permanent magnet,

(k) a first central electrode arranged on the main surface or inside of the ferrite and one end electrically connected to the first input and output port and the other end electrically connected to the second input and output port,

(1) The first central electrode is electrically insulated from the second central electrode disposed on the main surface or inside of the ferrite and one end is electrically connected to the second input and output port and the other end is electrically connected to the third port,

(m) a first matching capacitor electrically connected between the first input and output port and the second input and output port,

(n) a second matching capacitor electrically connected between the second input and output port and the third port, and

(o) a resistor electrically connected between the third port and ground,

(p) wherein the inductance L1 of the first center electrode is different from the inductance L2 of the second center electrode.

In order to make the inductance L1 of the first center electrode different from the inductance L2 of the second center electrode, for example, the electrode width, electrode thickness, electrode length, electrode number, electrode interval, etc. of the two may be different. Also, the ferrite can be rectangular or circular in plan view. Moreover, the electrostatic capacitances C1 and C2 of the first and second matching capacitors are respectively set to optimum values in conjunction with the inductances L1 and L2 of the first and second center electrodes.

According to the above structure, when the inductance L1 of the first center electrode is smaller than the inductance L2 of the second center electrode (when L1<L2), as the difference between L1 and L2 increases, the isolation bandwidth narrows and the insertion loss bandwidth changes. Conversely, when the inductance L1 of the first center electrode is greater than the inductance L2 of the second center electrode (L1>L2), as the difference between L1 and L2 increases, the isolation bandwidth changes and the insertion loss bandwidth narrows.

The two-port isolator of the present invention has a metal case for packing permanent magnets, ferrite, and first and second center electrodes, and the metal case has an upper portion, a bottom portion, and a pair of opposite sides connecting the upper portion and the bottom portion. Either one of the first center electrode and the second center electrode is arranged in a direction substantially perpendicular to the side surface, and the other center electrode is arranged in a direction substantially parallel to the side surface.

According to the above structure, the center electrode arranged so as to be substantially perpendicular to the side surface connecting the upper part and the bottom part of the metal box is likely to have a ground current flow through the upper part and the bottom part, and the center electrode arranged so as to be substantially parallel to the side part is not. A ground current tends to flow through the upper surface and the bottom surface. Therefore, even if the first center electrode and the second center electrode have the same shape, the inductances L1 and L2 of the two can be made different.

Also, a first input-output external electrode electrically connected to the first input-output port and a second input-output external electrode electrically connected to the second input-output port may be respectively provided at a central position of a pair of side faces of the two-port type isolator. . As a result, when mounting a two-port isolator on a printed circuit board such as a mobile phone, the isolator can be mounted on a printed circuit board in which input signal lines and output signal lines are set to the left and right by rotating the isolator 180 degrees. Therefore, there is no need to make two types of two-port type isolators according to the direction of the input signal line and the output signal line of the printed circuit board.

Furthermore, since the communication device of the present invention includes the above-mentioned two-port isolator, its characteristics are improved.

Description of drawings

FIG. 1 is an exploded perspective view showing an embodiment of a two-port isolator according to the present invention.

FIG. 2 is a top view of the center electrode assembly shown in FIG. 1 .

FIG. 3 is an exploded perspective view of the laminated substrate shown in FIG. 1 .

Fig. 4 is an external perspective view of the two-port isolator shown in Fig. 1 .

FIG. 5 is an electrical equivalent circuit diagram of the two-port isolator shown in FIG. 1 .

Fig. 6 is a graph showing isolation characteristics.

Fig. 7 is a graph showing insertion loss characteristics.

FIG. 8 is a graph showing input return loss characteristics.

FIG. 9 is a graph showing output reflection loss characteristics.

FIG. 10 is a graph showing the relationship between the ratio of C1/C2 and the degree of isolation.

FIG. 11 is a graph showing the relationship between the ratio of C1/C2 and insertion loss.

FIG. 12 is a graph showing the relationship between the ratio of C1/C2 and the output reflection loss.

Fig. 13 is an exploded perspective view showing another embodiment of the two-port isolator according to the present invention.

FIG. 14 is an exploded perspective view of the laminated substrate shown in FIG. 13 .

Fig. 15 is an exploded perspective view showing still another embodiment of the two-port isolator according to the present invention.

Fig. 16 is an exploded perspective view of the laminated substrate shown in Fig. 15 .

FIG. 17 is an electrical equivalent circuit diagram of the two-port isolator shown in FIG. 15 .

Fig. 18 is a graph showing isolation characteristics.

Fig. 19 is a graph showing insertion loss characteristics.

Fig. 20 is a graph showing input return loss characteristics.

Fig. 21 is a graph showing output reflection loss characteristics.

FIG. 22 is a graph showing the relationship between the ratio of C1/C2 and the degree of isolation.

FIG. 23 is a graph showing the relationship between the ratio of C1/C2 and insertion loss.

FIG. 24 is a graph showing the relationship between the ratio of C1/C2 and the input return loss.

Fig. 25 is a circuit block diagram of a communication device according to the present invention.

Fig. 26 is a bottom view showing a modified example of the center electrode assembly.

Fig. 27 is a bottom view showing another modified example of the center electrode assembly.

Fig. 28 is a plan view showing still another modified example of the center electrode assembly.

Fig. 29 is a plan view showing still another modified example of the center electrode assembly.

Fig. 30 is a plan view showing still another modified example of the center electrode assembly.

Fig. 31 is a plan view showing still another modified example of the center electrode assembly.

In the accompanying drawings, 1, 1A, 1B are lumped constant type isolators, 4 is a metal upper case, 8 is a metal lower case, 9 is a permanent magnet, 13, 13A～13H are center electrode assemblies, and 14 is an input external Electrode, 15 is output external electrode, 16 is ground external electrode, 20 is ferrite, 21 is first center electrode, 22 is second center electrode, 21a, 21b, 22a, 22b are ends, 30, 30A, 30B 41 to 45 are dielectric sheets, 55, 56, and 57 are capacitor electrodes, 58 is a ground electrode, 220 is a mobile phone, 25 and 26 are matching capacitors, 27 is a resistor, and P1 is an input port (the first input output port), P2 is the output port (the second input and output port), and P3 is the ground port (the third port).

Detailed ways

Embodiments of a two-port isolator and a communication device according to the present invention will be described below with reference to the drawings.

Embodiment 1 (Fig. 1 to Fig. 12)

FIG. 1 shows an exploded perspective view of an embodiment of a two-port isolator according to the present invention. This two-port isolator 1 is a lumped constant type isolator. As shown in FIG. 1, a two-port type isolator 1 generally has a metal case composed of a metal upper case 4 and a metal lower case 8, a permanent magnet 9, an electrode assembly 13 composed of a ferrite 20 and center electrodes 21 and 22 and the laminated substrate 30 .

The metal upper case 4 is substantially box-shaped and consists of an upper portion 4a and four side portions 4b. The metal lower case 8 is composed of a bottom portion 8a and left and right side portions 8b. The metal upper case 4 and the metal lower case 8 form a magnetic circuit, so they are made of ferromagnetic material such as soft iron, and the surface is plated with Ag or Cu.

In the center electrode assembly 13 , two sets of first and second center electrodes 21 and 22 are arranged on the upper surface of the disk-shaped microwave ferrite 20 so as to cross each other perpendicularly through an insulating layer (not shown). In Embodiment 1, the center electrodes 21, 22 are formed in two rows. Both end portions 21a, 21b, 22a, and 22b of the first center electrode 21 and the second center electrode 22 extend on the lower surface of the ferrite 20, and the respective end portions 21a to 22b are separated from each other.

As shown in FIG. 2 , the electrode width W1 of the first central electrode 21 is different from that of the second central electrode 22 . Accordingly, the inductance L1 of the first center electrode 21 is different from the inductance L2 of the second center electrode 22 . In Embodiment 1, the inductances L1 and L2 are made different by making the electrode widths W1 and W2 different, but it is not necessarily limited to this. The electrode length 11 of a center electrode is different from the length 12 of the second center electrode, so that the electrode interval S1 of the first center electrode and the electrode interval S2 of the second center electrode 22 are different, or the combination of the above points can also make the inductance L1 and L2 is different.

Here, the narrower the electrode widths W1, W2 of the center electrodes 21, 22, the larger the inductances L1, L2. The thinner the electrode thicknesses t1 and t2 are, the larger the inductances L1 and L2 are. The longer the electrode lengths 11, 12 are, the larger the inductances L1, L2 are. The narrower the electrode intervals S1, S2, the larger the inductances L1, L2.

The center electrodes 21, 22 can be formed by wrapping copper foil on the ferrite 20, or by printing silver paste on or inside the ferrite 20. Alternatively, as described in JP-A-9-232818, it may be formed using a laminated substrate. However, the printing method makes the positional accuracy of the center electrodes 21 and 22 high, so that the connection with the multilayer substrate 30 is stable. In particular, in this case, when connection is performed with the connection electrodes 51 to 54 (described later) for the fine center electrodes, the method of printing and forming the center electrodes 21 and 22 is good in reliability and operability.

As shown in FIG. 3 , the laminated substrate 30 is composed of connecting electrodes 51 to 54 for the center electrodes, a dielectric sheet 41 with capacitive electrodes 55 and 56 and a resistor 27 on the back, a dielectric sheet 42 with a capacitive electrode 57 on the back, and The dielectric sheet 43 provided with the ground electrode 58 on the back surface, and the dielectric sheet 45 provided with the input external electrode 14 , the output external electrode 15 and the ground external electrode 16 are configured. The connection electrode 51 for the center electrode serves as the input port P1, the connection electrodes 53 and 54 for the center electrode serve as the output port P2, and the connection electrode 52 for the center electrode serves as the third port P3.

This laminated substrate 30 is fabricated as follows. That is, the dielectric sheets 41 to 45 are made of a low-temperature sintered dielectric material containing Al ₂ O ₃ as a main component, SiO ₂ , SrO ₂ , CaO, PbO, Na ₂ O, K ₂ O, MgO, BaO , CeO ₂ , B ₂ O ₃ in one or more as a secondary component.

Make shrinkage suppression sheets 46, 47 that suppress the laminated substrate 30 from firing and shrinking in the substrate plane direction (X-Y direction), so that they will not be fired under the firing conditions of the laminated substrate 30 (especially below the firing temperature of 1000°C) . The material of the shrinkage suppressing sheets 46 and 47 is a mixed material of alumina powder and stabilized zirconia powder. The thickness of the sheets 41 to 47 is about 10 μm to 200 μm.

Electrodes 51 to 58 are formed on the back surfaces of the sheets 41 to 43 and 46 by pattern printing or the like. As materials for the electrodes 51-58, Ag, Cu, Ag-Pd, etc. which have low resistivity and can be fired simultaneously with the dielectric sheets 41-45 can be used. The electrodes 51 to 58 have a thickness of about 2 μm to 20 μm. The thickness of the electrodes 51 to 58 and the like is usually set to be twice or more the thickness of the skin.

The resistor 27 is formed on the back surface of the dielectric sheet 41 by pattern printing or the like. As the material of the resistor 27, cermet, carbon, ruthenium, or the like is used. The resistor 27 can also be formed by printing on the upper surface of the laminated substrate 30, and can also be formed by a chip resistor.

Via holes 60 , side via holes 65 and external electrodes 14 to 16 are formed by forming holes for vias in dielectric sheets 41 to 45 in advance by laser processing or press processing, and then filling the holes with conductive paste.

The matching capacitor 25 is formed by making the capacitor electrode 57 face the capacitor electrode 45 with the dielectric sheet 42 sandwiched therebetween. Furthermore, the matching capacitor 26 is formed by making the capacitor electrode 57 face the capacitor electrode 56 and the ground electrode 58 with the dielectric sheets 42 and 43 sandwiched therebetween. These matching capacitors 25 and 26 and resistor 27 together with electrodes 51 to 54 , external electrodes 14 to 16 and via holes 60 and 65 constitute a circuit inside laminated substrate 30 .

The above-mentioned dielectric sheets 41 to 45 are laminated, and the laminated body of the dielectric sheets 41 to 45 is sandwiched by the shrinkage suppression sheets 46 and 47 from both upper and lower sides of the laminated body, followed by firing. Thus, after the sintered body is obtained, the unsintered shrinkage suppressing material is removed by ultrasonic cleaning or wet honing to obtain the multilayer substrate 30 shown in FIG. 1 .

The input external electrode 14 , the output external electrode 15 , and the ground external electrode 16 are respectively provided at both ends of the multilayer substrate 30 . The input external electrode 14 is electrically connected to the capacitor electrode 55 , and the output external electrode 15 is electrically connected to the capacitor electrode 57 . The ground external electrode 16 is electrically connected to the ground electrode 58 . Then, Au plating was performed using the Ni plating layer as a base. The Ni plating enhances the bonding strength of the Ag and Au plating of the electrodes. The Au plating layer makes the wettability of the solder good, and at the same time, the electrical conductivity is high, so that the loss of the isolator 1 is small.

The laminated substrate 30 is usually produced in a mother board state. Half-cut grooves are formed on the mother board at predetermined intervals, and the laminated substrate 30 of a desired size is obtained from the mother board by breaking along the grooves. Alternatively, the mother board can be cut with a microtome or a laser to cut out laminated substrates 30 of a desired size.

The laminated substrate 30 thus obtained has matching capacitors 25, 26 and a resistor 27 inside. Make the matching capacitors 25 and 26 according to the accuracy of the required electrostatic capacitance. However, trimming is performed before connecting the matching capacitors 25 and 26 to the center electrodes 21 and 22 . That is, in the multilayer substrate 30 in a single state, the internal (second layer) capacitive electrodes 55 and 56 are trimmed (trimmed) together with the dielectric body on the surface layer. Cutting machines or YAG fundamental wave, 2nd harmonic, and 3rd harmonic lasers are used for trimming. Using a laser enables high-speed and high-precision processing. The multilayer fundamental wave 30 in the motherboard state can also be trimmed efficiently.

In this way, since the capacitive electrodes 55 and 56 near the upper surface of the multilayer substrate 30 are used as capacitive electrodes for trimming, the thickness of the dielectric layer removed during trimming can be minimized. In addition, since the number of electrodes that become obstacles to trimming is reduced (only the connecting electrodes 51 to 54 in the case of the first embodiment), the capacitive electrode area that can be trimmed is expanded, so that the adjustment range of the electrostatic capacity can be enlarged.

The multilayer substrate 30 also has a built-in resistor 37, and like the matching capacitors 25 and 26, the resistor 27 is also trimmed together with the surface layer dielectric, so that the resistance value R can be adjusted. Even when the width of the resistor 27 becomes thinner at ~, the resistance value R increases, so it is cut to the middle in the width direction.

The above constituent parts are assembled as follows. That is, as shown in FIG. 1 , the permanent magnet 9 is fixed to the top of the metal upper case 4 with an adhesive. The end portions 21a to 22b of the center electrodes 21 and 23 of the center electrode assembly 13 are electrically connected to the connection electrodes 51 to 54 for center electrodes formed on the surface of the laminated substrate 30 with solder 80, and mounted on the laminated substrate 30. Center electrode assembly 13 . The soldering of the center electrodes 21 , 22 and the connection electrodes 51 to 54 for center electrodes can be efficiently performed also on the multilayer substrate 30 in the motherboard state.

The laminated substrate 30 is mounted on the bottom surface 8a of the metal lower case 8, and the ground electrode 58 disposed on the lower surface of the laminated substrate 30 is connected to and fixed to the bottom surface 8a by solder 80. Thus, the ground port 16 facilitates the electrical connection to the bottom surface portion 8a.

Then, the metal lower case 8 and the metal upper case 4 are joined with their respective side portions 8b and 4b with solder or the like to form a metal case, which also functions as a yoke. That is, the metal case forms a magnetic circuit surrounding the permanent magnet 9 , the center electrode assembly 13 and the laminated substrate 30 . The permanent magnet 9 also applies a DC magnetic field to the ferrite 20 .

In this way, the two-port type isolator 1 shown in FIG. 4 is obtained. FIG. 5 is an electrical equivalent circuit of the isolator 1 . One end portion 21a of the first center electrode 21 is electrically connected to the input external electrode 14 through an input port (center electrode connection electrode 51). The other end portion 21b of the first center electrode 21 is electrically connected to the output external electrode 15 through the output port P2 (connection electrode 54 for center electrode). One end portion 22a of the second center electrode 22 is electrically connected to the output external electrode 15 through the output port P2 (center electrode connection electrode 53). The other end portion 22b of the second center electrode 22 is electrically connected to the ground external electrode 16 through the third port P3 (connection electrode 52 for center electrode). A parallel RC circuit composed of a matching capacitor 25 and a resistor 27 is electrically connected to the input port

Between P1 and output port P2. The matching capacitor 26 is connected between the output port P2 and the third port P3. The third port P is electrically connected to ground.

The two-port isolator 1 composed of the above components makes the inductance L1 of the first center electrode 21 different from the inductance L2 of the second center electrode 22, and when L1<L2, as the difference between L1 and L2 becomes larger, the isolation bandwidth narrower, the bandwidth of the insertion loss becomes wider. Conversely, when L1>L2, as the difference between L1 and L2 becomes larger, the isolation bandwidth becomes wider and the insertion loss bandwidth becomes narrower. That is, by adjusting the values of L1 and L2, the isolation bandwidth and the insertion loss bandwidth can be adjusted according to the required specifications of the communication system.

On the other hand, as the inductances L1 and L2 of the center electrodes 21 and 22 are made different from each other, the capacitances C1 and C2 of the matching capacitors 25 and 26 also need to be made different (set to optimum capacitances C1 and C2). That is, it is necessary to unify the parallel resonance circuits of L1 and C1 and L2 and C2 to the same resonance frequency. Therefore, in the present invention, the matching capacitors 25 and 26 are formed by the electrodes 55 to 58 arranged in the multilayer substrate 30 . Thus, by making the opposing areas and intervals of the electrodes 55 to 58 different, the capacitances C1 and C2 of the matching capacitors 25 and 26 can be easily made different.

The curves of Fig. 6, Fig. 7, Fig. 8 and Fig. 9 respectively show the inductance L1, L2 and matching capacitance of the first and second central electrodes 21, 22 in the two-port type isolator 1 as shown in Table 1-1 The isolation characteristics, insertion loss characteristics, input reflection loss characteristics and output reflection loss characteristics when the static capacitances C1 and C2 of 25 and 26 are changed in various ways.

Here, as the ferrite 20, a ferrite having a diameter of 2.0 mm and a thickness of 0.4 mm is used. Furthermore, the electrode width W of the center electrodes 21 and 22 is set to 0.2 mm, the electrode interval S is set to 0.2 mm, the electrode length 1 is set to 2 mm, and the self-inductance is set to 0.7 nH. Also, the electrode width W of the central electrodes 21 and 22 is 0.5mm, the electrode spacing S is 0.2mm, the electrode length 1 is 2mm, and the self-inductance is set to 0.5nH. Furthermore, the electrode width W of the central electrodes 21 and 22 is 0.1 mm, the electrode spacing S is 0.1 mm, the electrode length 1 is 2 mm, and the self-inductance is set to 1.0 nH. The resistance values R of the resistors 27 are both 60Ω. The inductance in Table 1-1 is the self-inductance of the center electrodes 21 and 22 when the relative magnetic permeability is assumed to be 1. In fact, the value obtained by multiplying this value by the effective magnetic permeability of the ferrite 20 is equal to the inductance L1 and L2. Table 1-2 summarizes the worst values in the frequency band of 893MHz to 960MHz.

【Table 1】

(Table 1-1) The self-inductance of the first center electrode 21 The self-inductance of the second center electrode 22 The static capacitance C1 of the matching capacitor 25 The static capacitance C2 of the matching capacitor 26 Comparative example 1 0.7nH 0.7nH 22pF 22pF Example 1 0.5nH 1.0nH 32pF 15pF Example 2 0.1nH 0.5nH 15pF 32pF

(Table 1-2) Input return loss (dB) Insertion loss(dB) Isolation (dB) Output reflection loss (dB) Comparative example 1 22.4 0.75 12.2 11.8 Example 1 23.0 0.47 9.5 14.8 Example 2 22.6 1.18 15.5 9.6

From Figures 6 to 9 and Tables 1-2, it can be seen that, as in Example 1, the self-inductance of the first center electrode 21 is made smaller than the self-inductance of the second center electrode 22, although the isolation becomes worse, the insertion loss and reflection loss improve.

On the contrary, it can be seen that if the self-inductance of the first center electrode 21 is made larger than the self-inductance of the second center electrode 22 as in Example 2, although the insertion loss and the reflection loss are deteriorated, the isolation is improved.

In this way, the self-inductances of the two center electrodes 21 and 22 are different, so that the insertion loss and isolation can be optimized, and the isolator 1 with excellent characteristics can be provided.

The two-port type isolator used in mobile communication equipment usually requires an insertion loss of 1.2dB or less and an isolation of 8.0dB or more. Therefore, by making various changes to the electrostatic capacitance ratio C1/C2 of the matching capacitors 25 and 26, it is found that A two-port type isolator1 that satisfies this condition. Table 2 shows the evaluation results, and the curves in Fig. 10, Fig. 11 and Fig. 12 show the isolation characteristics, insertion loss characteristics and output reflection loss characteristics, respectively.

【Table 2】

(Table 2) C1/C2 Input return loss (dB) Insertion loss(dB) Isolation (dB) Output reflection loss (dB) 0.33 22.70 1.60 17.20 7.70 0.50 22.60 1.18 15.50 9.60 0.66 22.00 0.97 13.50 10.30 0.90 22.10 0.80 12.70 11.40 1.00 22.40 0.75 12.20 11.80 1.10 22.10 0.70 11.80 12.10 1.50 22.20 0.60 10.60 12.90 2.00 23.00 0.47 9.50 14.80 3.00 23.20 0.38 8.00 16.20 3.50 24.00 0.35 7.10 16.90

It can be seen from Table 2 and Figures 10 and 11 that when a two-port isolator 1 with excellent isolation within the range of insertion loss below 1.2dB and isolation above 8.0dB is desired, the value of C1/C2 is designed to satisfy the relation 0.5≤C1/C2≤0.9 is preferred. The reason is that if C1/C2 is less than 0.9, the isolation can be improved by 0.5dB, and when C1/C2 is less than 0.5, the isolation can be further improved, but the insertion loss exceeds 1.2dB, which is too bad to be practical.

When a two-port type isolator 1 with an insertion loss of 1.2dB or less and an isolation of 8.0dB or more is desired, it is better to design the value of C1/C2 to satisfy the relationship 1.1≤C1/C2≤3.0. The reason is that when C1/C2 is above 1.1, the insertion loss can be improved by 0.05dB, and when C1/C2 is more than 3.0, the insertion loss can be further improved, but the isolation exceeds 8.0dB, which is too bad to be practical.

In the case of a 3-port type isolator (an isolator having three center electrodes such as the first to third center electrodes), such as JP-A-2001-185914, JP-A-2001-203007, and JP-A-2001-203508 As described in the Publication No. 1, a structure in which the inductance of the center electrodes is made different is known. However, in these 3-port type isolators, the structurally asymmetric part is adjusted by electrode width and the like.

On the contrary, the present invention positively makes an asymmetric structure, and sets isolation and insertion loss to desired characteristics. Furthermore, although the 3-port type isolator makes the inductance of the center electrodes different, it cannot make a trade-off adjustment between the isolation bandwidth and the insertion loss bandwidth. Only the two-port type isolator of the present invention in which the two ends 21a, 21b of the center electrode 21 are connected to the input and output ports P1, P2 can obtain this effect.

Embodiment 2 (Figure 13 and Figure 14)

A two-port isolator 1A shown in FIG. 13 is the same as the two-port isolator 1 of the first embodiment except for a center electrode assembly 13A and a laminated substrate 30A.

The center electrode assembly 13A is arranged such that the first and second center electrodes 21 , 22 cross each other on the upper surface of the ferrite 20 through an insulating layer (not shown). The shapes (electrode width, electrode thickness, electrode length, electrode interval, etc.) of the first and second center electrodes 21, 22 are the same.

As shown in FIG. 14 , the components of the laminated substrate 30A include connection electrodes 51 to 54 for center electrodes, a dielectric sheet 41 with a capacitive electrode 55 and a resistor 27 on the back, a dielectric sheet 42 with a capacitive electrode 57 on the back, and a dielectric sheet 42 with a capacitive electrode 57 on the back. The dielectric sheet 43 of the ground electrode 58, the dielectric sheet 45 provided with the input external electrode 14, the output external electrode 15, and the ground external electrode 16, and the like. This laminated substrate 30A is fabricated by the same method as that of the laminated substrate 30 of the first embodiment.

The capacitor electrode 57 is opposite to the capacitor electrode 55 and sandwiches the dielectric sheet 42 to form the matching capacitor 25 . The capacitor electrode 57 is opposite to the ground electrode 58 and sandwiches the dielectric sheet 43 to form the matching capacitor 26 .

The connection electrodes 51 to 54 for the center electrode are arranged near the center of each of the four sides of the multilayer substrate 30A. The input external electrode 14 and the output external electrode 15 are arranged at the center of two opposing sides on the multilayer substrate 30A. The connecting electrode 51 for a center electrode serves as an input port P1, the connecting electrodes 53 and 54 for a center electrode serve as an output port P2, and the connecting electrode 52 for a center electrode serves as a third port P3.

Center electrode assembly 13A having the above structure is mounted on laminate substrate 30A, and one of the two sets of center electrodes 21 and 22 is perpendicular to side surface 8b of metal lower case 8 joined to metal upper case 4 . The center electrode 22 disposed in the direction perpendicular to the opposite side portion 8b makes it easy for the ground current to flow to the upper portion 4a and the bottom portion 8a of the metal box, and the center electrode 21 disposed in the direction parallel to the opposite side portion 8b makes it difficult for the ground current to flow to the metal box. The upper part 4a and the bottom part 8a of the case. Therefore, even though the center electrodes 21 and 22 have the same shape, their inductances L1 and L2 are different.

Accordingly, the two-port isolator 1A obtains the same effect as the isolator 1 of the first embodiment. The ground current is generated by a power supply device (not shown) connected to the input and output external electrodes 14, 15, and flows through various paths in the isolator 1A. For example, the ground current flows in the order of input external electrode 14-central electrode 21-central electrode 22-ground external electrode 16, or input external electrode 14-central electrode 21-matching capacitor C2 (displacement current)-ground external electrode 16 and path order circulation.

In the second embodiment, the input external electrode 14 and the output external electrode 15 are provided at the center of a pair of side surfaces of the isolator 1A that face each other. Therefore, when the isolator 1A is mounted on a printed circuit board such as a mobile phone, the isolator 1A can be rotated 180 degrees to be mounted on a printed circuit board in which the input signal line and the output signal line are arranged in opposite directions. Therefore, there is no need to fabricate two types of isolator 1A according to the direction of the input signal line and the output signal line of the printed circuit board, and the cost of the isolator 1A can be reduced.

In particular, in this two-port isolator 1A, when the port P1 is used as the input port and the port P2 is used as the input port, the return loss frequency characteristics are greatly different, and it is not necessary to manufacture not only the direction of the magnetic field (the NS direction of the permanent magnet 9 is opposite) but also The internal structure of the 2-way isolator 1A is changed, so the cost reduction effect is large.

Embodiment 3 (Fig. 15 to Fig. 24)

The two-port isolator 1B shown in FIG. 15 is the same as the two-port isolator 1 of the first embodiment except for the center electrode assembly 13B and the laminated substrate 30B.

The center electrode assembly 13B is arranged such that the first and second center electrodes 21 , 22 cross each other on the upper surface of the ferrite 20 through an insulating layer (not shown). The shapes (electrode width, electrode thickness, electrode length, electrode interval, etc.) of the first and second center electrodes 21, 22 are the same.

As shown in FIG. 16 , the components of the laminated substrate 30B include connecting electrodes 51 to 53 for center electrodes, a dielectric sheet 41 with capacitive electrodes 55 and 59 and resistors 27 on the back, a dielectric sheet 42 with capacitive electrodes 57 on the back, The dielectric sheet 43 on which the ground electrode 58 is provided on the back, the dielectric sheet 45 on which the input external electrode 14 , the output external electrode 15 , and the ground external electrode 16 are provided, and the like.

The capacitor electrode 57 is opposite to the capacitor electrodes 55, 59, and sandwiches the dielectric sheet 42 to form matching capacitors 25, 26 respectively.

The connecting electrode 53 for the center electrode is in the shape of a long strip, and one end 53 b thereof is electrically connected to the capacitive electrode 57 through the via hole 60 provided in the dielectric sheets 41 and 42 . Thus, the actual electrode length of the first center electrode 21 is the length of the first center electrode 21 itself plus the length from the end 53a of the center electrode connection electrode 53 (the end on the welding center electrode 21 side) to the connection via hole. 60 position length. The actual electrode lengths of the first center electrode 21 and the second center electrode 22 can be adjusted by changing the position of the via hole 60 .

As a result, the actual inductance L1 of the first center electrode 21 and the actual inductance L2 of the second center electrode 22 can be made different, and the isolation bandwidth and insertion loss bandwidth of the two-port isolator 1B can be adjusted according to the required specifications of the communication system. At this time, the position where the center electrode connection electrode 53 is connected to the via hole 60 is the position of the output port P2. Moreover, the connection electrode 51 for center electrodes is an input port P1, and the connection electrode 52 for center electrodes is a 3rd port P3.

It is also possible to reduce the number of via holes 60 and connection locations formed on the laminated substrate 30B, thereby reducing manufacturing costs. Moreover, by reducing the number of via holes 60, the electrode area that can be formed in a sheet can be enlarged, and the electrostatic capacitance of the matching capacitors 25, 26 can be increased.

FIG. 27 is an electrical equivalent circuit of the two-port isolator 1B obtained as described above. An LC parallel resonant circuit composed of a first central electrode 21 and a first matching capacitor 25 is connected between the input port P1 and the output port P2. An LC parallel resonant circuit composed of the second center electrode 22 and the second matching capacitor 26 is connected between the output port P2 and the third port P3. A terminating resistor 27 is also connected between the third port P3 and the grounded external electrode 16 .

The curves of Fig. 18, Fig. 19, Fig. 20 and Fig. 21 respectively show the actual inductance L1, L2 and matching capacitance 25 of the first and second center electrodes 21, 22 of the two-port type isolator 1B as shown in Table 3-1 , The isolation characteristics, insertion loss characteristics, input reflection characteristics and output reflection loss characteristics of static capacitance C1 and C2 of 26 for various changes. The resistance values R of the resistors 27 are both 60Ω. The inductance in Table 3-1 is the actual self-inductance of the central electrodes 21 and 22 when the relative magnetic permeability is assumed to be 1. In fact, the value obtained by multiplying the inductance by the effective magnetic permeability of the ferrite 20 is equal to the inductance L1 and L2. Table 3-2 summarizes the worst values in the 893MHz～960MHz frequency band.

【table 3】

(Table 3-1) The self-inductance of the first center electrode 21 The self-inductance of the second center electrode 22 The static capacitance C1 of the matching capacitor 25 The static capacitance C2 of the matching capacitor 26 Comparative example 2 0.7nH 0.7nH 22pF 22pF Example 3 0.5nH 1.0nH 32pF 15pF Example 4 1.0nH 0.5nH 15pF 32pF

(Table 3-2) Input return loss (dB) Insertion loss(dB) Isolation (dB) Output reflection loss (dB) Comparative example 2 12.0 1.11 9.9 22.2 Example 3 14.3 0.75 8.0 22.5 Example 4 9.3 1.60 12.0 22.6

From Figures 18 to 21 and Table 3-2, it can be seen that, as in Example 3, the self-inductance of the first center electrode 21 is made smaller than the self-inductance of the second center electrode 22, although the isolation becomes worse, the insertion loss and reflection loss improve.

On the contrary, it can be seen that, as in Example 4, if the self-inductance of the first center electrode 21 is made larger than the self-inductance of the second center electrode 22, although the insertion loss and reflection loss are deteriorated, the isolation is improved.

In this way, the self-inductances of the two center electrodes 21 and 22 are different, so that insertion loss and isolation can be optimized, and an isolator 1B with excellent characteristics can be provided.

The two-port type isolator used in mobile communication equipment usually requires an insertion loss of 1.2dB or less and an isolation of 8.0dB or more. Therefore, by making various changes to the electrostatic capacitance ratio C1/C2 of the matching capacitors 25 and 26, it is found that Two-port type isolator 1B that satisfies this condition. Table 4 shows the evaluation results, and the curves in Fig. 22, Fig. 23 and Fig. 24 show the isolation characteristics, insertion loss characteristics and input return loss characteristics, respectively.

【Table 4】

(Table 4) C1/C2 Input return loss (dB) Insertion loss(dB) Isolation (dB) Output reflection loss (dB) 0.33 7.70 2.20 13.50 23.00 0.50 9.30 1.60 12.00 22.60 0.66 11.30 1.42 10.80 21.80 0.90 11.60 1.18 10.20 21.90 1.00 12.00 1.11 9.90 22.20 1.10 12.30 1.06 9.60 21.80 1.50 13.30 0.92 8.70 21.90 2.00 14.30 0.75 8.00 22.50 3.00 17.10 0.56 6.60 23.00 3.50 18.00 0.48 6.30 24.10

It can be seen from Table 4 and Figure 22 and Figure 23 that the value of C1/C2 is designed to satisfy the relationship 1.1≤C1/C2≤2.0, and a two-port isolator with an insertion loss of less than 1.2dB and an isolation of more than 8.0dB can be obtained 1B.

Embodiment 4 (Figure 25)

Embodiment 4 The communication device of the present invention will be described by taking a mobile phone as an example.

FIG. 25 is a circuit block diagram of the RF (radio frequency) part of the mobile phone 220. As shown in FIG. In Fig. 25, 222 is an antenna element, 223 is a duplexer, 231 is a transmitting side isolator, 232 is a transmitting side amplifier, 233 is a transmitting side interstage bandpass filter, 234 is a transmitting side mixer, 235 is a receiving side Side amplifier, 236 is the receiving side interstage bandpass filter, 237 is the receiving side mixer, 238 is the voltage controlled oscillator, 239 is the local bandpass filter.

Here, as the transmission-side isolator 231, the two-port isolators 1, 1A, and 1B of Embodiments 1 to 3 described above can be used. By installing these isolators, a mobile phone with improved electrical characteristics and high reliability can be realized.

Other implementation forms

The present invention is not limited to the above-described embodiments, and various changes can be made within the scope of the gist. For example, by reversing the N pole and S pole of the permanent magnet 9, the input port P1 and the output port P2 can be switched.

The center electrode assembly can also be changed in various ways. For example, as in the center electrode assembly 13C shown in FIG. 26 , the lengths of the center electrodes 21 provided on the rear surface of the ferrite 20 can be extended by 13 in the longitudinal direction, so that the lengths of the center electrodes 21 and 22 can be different. At this time, the positions of the connection electrodes 51 and 54 for the center electrodes of the multilayer substrate 30 are moved to the inner side. Ends 21b and 22a of the center electrodes 21 and 22 disposed on the rear surface of the ferrite 20 may also be electrically connected as in the center electrode assembly 13D shown in FIG. 27 . In this case, one of the connection electrodes 53 and 54 for the center electrode of the multilayer substrate 30 can be omitted, and the number of via holes can be reduced.

Alternatively, as in the center electrode assemblies 13E, 13F, and 13G shown in FIGS. 28 to 30 , the center electrodes 21 and 22 may not be parallel to each other, may be bent, and may have different numbers of electrodes. Furthermore, as in the center electrode assembly 13H shown in FIG. 31, a rectangular ferrite 20 can be used. At this time, the first center electrode 21 is arranged parallel to the short side of the ferrite 20 , and the second center electrode 22 is arranged parallel to the long side of the ferrite 20 .

As can be seen from the above description, according to the present invention, by setting the inductances of the first center electrode and the second center electrode to different values, insertion loss and isolation can be optimized, and a two-port isolator having excellent characteristics can be provided. Therefore, a high-performance, high-reliability, and small-sized two-port type isolator and communication device can be obtained.

Claims (15)

1. a two ends shape of the mouth as one speaks isolator is characterized in that, comprises

Permanent magnet,

By described permanent magnet apply D.C. magnetic field ferrite,

Be configured in that described ferritic interarea or an inner and end are electrically connected first input/output port and the other end be electrically connected second input/output port first central electrode,

With described first central electrode under the state of electric insulation cross-over configuration described ferritic interarea or an inner and end be electrically connected second input/output port and the other end be electrically connected the 3rd port second central electrode,

Be connected electrically in first matching capacitance between described first input/output port and described second input/output port,

Be connected electrically between described first input/output port and described second input/output port resistance and

Be connected electrically in second matching capacitance between described second input/output port and described the 3rd port,

Described the 3rd port electrical ground, and the inductance L 1 of described first central electrode is different with the inductance L 2 of described second central electrode.

2. a two ends shape of the mouth as one speaks isolator is characterized in that, comprises

Permanent magnet,

By described permanent magnet apply D.C. magnetic field ferrite,

Be configured in that described ferritic interarea or an inner and end are electrically connected first input/output port and the other end be electrically connected second input/output port first central electrode,

With described first central electrode under the state of electric insulation cross-over configuration described ferritic interarea or an inner and end be electrically connected second input/output port and the other end be electrically connected the 3rd port second central electrode,

Be connected electrically in first matching capacitance between described first input/output port and described second input/output port,

Be connected electrically between described second input/output port and described the 3rd port second matching capacitance and

Be connected electrically in the resistance between described the 3rd port and the ground,

The inductance L 1 of described first central electrode is different with the inductance L 2 of described second central electrode.

3. two ends as claimed in claim 1 or 2 shape of the mouth as one speaks isolator is characterized in that,

The shape of described first central electrode is different with the shape of described second central electrode.

4. two ends as claimed in claim 1 or 2 shape of the mouth as one speaks isolator is characterized in that,

The electrode widths W 1 of described first central electrode is different with the electrode widths W 2 of described second central electrode.

5. two ends as claimed in claim 1 or 2 shape of the mouth as one speaks isolator is characterized in that,

The thickness of electrode t1 of described first central electrode is different with the thickness of electrode t2 of described second central electrode.

6. two ends as claimed in claim 1 or 2 shape of the mouth as one speaks isolator is characterized in that,

The electrode length 11 of described first central electrode is different with the electrode length 12 of described second central electrode.

7. two ends as claimed in claim 1 or 2 shape of the mouth as one speaks isolator is characterized in that, the electrode radical of described first central electrode is different with the electrode radical of described second central electrode.

8. two ends as claimed in claim 1 or 2 shape of the mouth as one speaks isolator is characterized in that,

Described first central electrode and second central electrode electrode radical separately is many, and the electrode gap S1 of first central electrode is different with the electrode gap S2 of second central electrode.

9. two ends as claimed in claim 1 shape of the mouth as one speaks isolator is characterized in that,

The direct capacitance C2 of the direct capacitance C1 of described first matching capacitance and described second matching capacitance satisfies relational expression 0.5≤C1/C2≤0.9.

10. two ends as claimed in claim 1 shape of the mouth as one speaks isolator is characterized in that,

The direct capacitance C2 of the direct capacitance C1 of described first matching capacitance and described second matching capacitance satisfies relational expression 1.1≤C1/C2≤3.0.

11. two ends as claimed in claim 2 shape of the mouth as one speaks isolator is characterized in that,

The direct capacitance C2 of the direct capacitance C1 of described first matching capacitance and described second matching capacitance satisfies relational expression 1.1≤C1/C2≤2.0.

12. two ends as claimed in claim 1 or 2 shape of the mouth as one speaks isolator is characterized in that,

Can with the described permanent magnet of packing, described ferrite, described first and second central electrodes,

Described can has a pair of mutual opposed side surface part that goes up facial, bottom surface sections and connect face and bottom surface sections on this, any central electrode of described first central electrode and described second central electrode is configured in the vertical direction of described side surface part, and another central electrode is configured in the direction parallel to described side surface part.

13. two ends as claimed in claim 1 or 2 shape of the mouth as one speaks isolator is characterized in that,

Middle position in a pair of mutual opposite side of two ends shape of the mouth as one speaks isolator is provided with first input and output outer electrode that is electrically connected described first input/output port and the second input and output outer electrode that is electrically connected described second input/output port respectively.

14. two ends as claimed in claim 1 or 2 shape of the mouth as one speaks isolator is characterized in that,

Overlooking described ferrite is rectangle, and described first central electrode is configured to parallel with one side of this rectangle, and described second electrode is configured to be parallel to the vertical edges on described one side.

15. a communicator is characterized in that,

Has two ends as claimed in claim 1 or 2 shape of the mouth as one speaks isolator.

Images