JPS6042918A - filter device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a filter inserted between a high-frequency signal transmission path, such as an antenna and a tuner of a television, FM radio, etc. The structure of a conventional example and its problems. As a filter to be inserted between the tuner and antenna of FM radio, television, etc., the coils, capacitors, etc. that make up the circuit are formed by coating them on both sides of a dielectric plate in a circuit pattern. is widely used because it is easy to mass produce and has uniform quality.The first circuit example is
As shown in the figure, 1 and 3 are people, output terminals, and 2 is a ground terminal. Coil L1. The condenser C1 constitutes a first resonant circuit, and the mater coil L2 and capacitor C2 constitute a second resonant circuit.

Figure 2 is an example of the circuit shown in Figure 1 being formed on a dielectric substrate.In Figure 2, 1 and 3 are input and output terminals, 2 is a ground terminal, and 5
6 is a dielectric substrate; 6 is a coil pattern of a coil L1; the coil pattern 61 is formed on the A side of the dielectric (lambda) plate 5; the coil pattern 6b is graded on the 8th side of the dielectric substrate 5; , Y is the coil pattern of the coil L2, and the coil pattern 7a is a dielectric material no. 10B and 10B are the electrode backs of capacitor C5.
7TL, the other capacitor C1 has a coil pattern 6a,
6b and 02 are formed equimetrically at opposing portions of the coil patterns 7a and 7b, respectively.

By the way, since the filter shown in FIG. 2 has a planar structure, there is a limit to how small it can be made.

In other words, there is a problem in that it is not possible to make the circuit smaller in size than the effective area occupied by the pattern constituting the circuit.

Therefore, if the circuit is laminated, the packaging density becomes ',K<' and the circuit can be made compact, but the problem arises that the magnetic flux emitted from the coils causes magnetic coupling between the coils, which impairs the characteristics.

Purpose of the Invention The purpose of the present invention is to use a method of forming a circuit pattern on a dielectric substrate, which is easy to mass-produce, and to create a flat structure with a textured structure (all-layered board), unlike the conventional planar structure. An object of the present invention is to provide a filter device.

Structure of the Invention In order to achieve this object, in the present invention, a first resonant circuit is all connected in parallel to the input and output terminals, and a second resonant circuit is connected in series to the input and output terminals. The second resonant circuit is electrically connected to the high potential side of the first resonant circuit, and is configured such that the first resonant circuit and the second resonant circuit are magnetically coupled, and this magnetic Explanation of an embodiment in which the coupling is configured such that the coupling coefficient is approximately 0.2 to 0.3 or less To explain the circuit configuration of Fig. 1, the circuit is divided into left and right sections by 4-4'. A first circuit and a second circuit are configured. Then, respective circuit configurations are formed on two dielectric substrates each having a smaller shape than the conventional one. For example, the structure is similar to that in which the dielectric substrate shown in FIG. 2 is divided into 4-4' left and right sections. The two dielectric substrates made up of these two circuit parts.''
Place the nails together through the gap or spacer, and then
A filter device is constructed by electrically connecting the circuit and the second circuit. By the way, the arrangement of the coil patterns formed on each dielectric substrate is such that when the dielectric substrates are superposed, the area where the coil patterns overlap vertically is reduced, for example, The area of the overlapping portion of the coil pattern is about A or less of the smaller area of the area surrounded by the outer coil pattern in each coil, and the thickness of the gap or spacer is about 0.3~0.51 JIm. By doing so, the magnetic coupling between the coils can be reduced. Coupling coefficient is approximately 0
．． If it is less than 1, it will not have a big effect on the characteristics, but if it is 0.2 to 0.
It is desirable to set it to 3 or less. With the above structure, even if a circuit pattern including a coil is deposited on a dielectric substrate and a laminated structure is formed, a small filter device can be constructed without impairing the characteristics. 11 is a diagram showing the arrangement of coil patterns; 11 is a first dielectric substrate; 12 is a diagram showing the arrangement of a coil pattern;
is a spacer, and 13 is a second dielectric substrate. Each dielectric substrate 11.13 has a 0.
A pattern similar to the divided circuit pattern is formed.

Suppose that terminals 1 and 2 shown in FIG. 1 are attached to the first dielectric substrate 11.
, coil L+, and capacitor c1, the coil pattern 6 shown in FIG. 2 is formed in the frame 14.
, that is, the coil pattern 6a.

This will form part 6b.

Next, when a second circuit including the terminal 3, coil L2, capacitor C2, and capacitor C3 shown in FIG. 1 is formed on the second dielectric substrate 13, the pattern of the coil L2 is
It may be formed within a frame 16 including the dotted line of the dielectric substrate 13. That is, the coil pattern 7, (,
7, a, '7 b) are deposited inside the entire frame 15. In FIG. Figure 4 is a side view of Figure 3. As shown in Figure 3, the coil pattern 7 of the coil L2 and the (zero overlapping part) are shown. Laminated pudding 1-filter can be constructed by depositing two circuits and superimposing them vertically via spacer 12 and connecting the two circuits with 4-conductor paste or jumper wire.Then, arrange the respective coil patterns. This reduces the number of nine parts 16 that are shifted and overlapped with each other.

FIG. 5 shows an equivalent circuit of the laminated filter 1-filter shown in FIG. 3. That is, the circuit pattern formed on the first dielectric substrate 11 constitutes a first resonant circuit, and the circuit pattern formed on the second dielectric substrate 13 constitutes a second resonant circuit. , the first resonant circuit is connected in parallel and column to the input and output terminals 1 and 3;
The resonant circuit constitutes a filter device connected in series to input and output terminals 1 and 3. Note that the second resonant circuit is connected to the high potential side of the first resonant circuit.

M is the mutual inductance caused between the pattern of coil L1 and the pattern of coil L2, and this ')11
The first resonant circuit and the second resonant circuit are magnetically coupled via mutual inductance 'klf.

L+'(r; J-leakage inductance of coil L1,
L2' is the leakage inductance of coil L2. Here, the value of 44+mutual inductance M in FIG. 5 changes depending on the area of the portion indicated by the overlapping 9 parts 16 in FIG. 3. The smaller the area of the portion 160, the smaller the value of the mutual inductance M. Therefore, the overlapped υ part 1
It is desirable that the area of the coils L1' and L2 be less than or equal to the smaller area of the area surrounded by the outer patterns of the coils L1' and L2. If the thickness of the spacer 12 is approximately 0.3 to 0.5 mm or more, then the coil L+
, Coupling between L2 (the number of threads can be reduced) If the coupling coefficient is about 0.1 or less, it will not have a big effect on the characteristics, but if it is 0.
It is preferable to set it to 2 to 0.3 or less. Therefore, by appropriately selecting the area of the overlapping portion 16 and the thickness of the spacer 12, a laminated purine I-filter can be constructed without impairing the characteristics. Unlike Fig. 3, the dielectric substrate 11°13
It is also possible to make the shapes of the shapes the same size and arrange the coil patterns in a staggered manner for polymerization.In that case, 1. The position of the coil can be easily determined, making manufacturing easy.

According to the present invention, as described in detail, the coils L+, L
A laminated Boulint filter can be constructed by reducing the coupling between the two (to a coupling coefficient of approximately 0.2 to 0.3 or less) without impairing the characteristics. By the way, when the coupling coefficient is small, the coils L+ and L2 are arranged so that the value of mutual inductance M between the coils L+ and L2 becomes a negative value (for example,
If the coils L+ and L2 are arranged so that the mutual inductance M becomes a positive value, the filter's passband tends to widen. The overband tends to become narrower. In other words, by adjusting the value of A'l', l7i-inductance M to suit all aspects, the characteristic of R can be obtained, and the KE'2, Coil L+, L
There is an advantage that the value of inductance 2 can be made small or large.

In addition, a method with good mass production efficiency, such as forming a complete circuit pattern (for example, by means of printing, etc.), can be used, and by stacking dielectric substrates, a shape that is smaller (higher packaging density) than a planar structure can be obtained, and each Since it has a simple structure in which the dielectric substrate is completely polymerized, it can be made at low cost.

Similarly, in the case of a device having a plurality of coils, each coil pattern may be shifted and the self-L1 layer may be formed in multiple layers.

Another advantage is that the quality of the first dielectric substrate and the second dielectric substrate can be changed depending on the timing.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a general bandpass filter, FIG. 2 is a plan view showing the structure of a conventional filter device, FIG. 3 is a plan view showing the arrangement in a filter device according to an embodiment of the present invention, and FIG. The figure shows the same filter units 6, 6a, eb,
7, 7a, 7b...-coil pattern, 11
...First dielectric substrate, 12...Spacer, 13...Second dielectric substrate, M...4
゛11 Name of agent for mutual induction Patent attorney Toshio Nakao and 1 other person 1st
Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] A first resonant circuit is connected in parallel to the input and output terminals, and a second resonant circuit is connected in series to the input and output terminals, and the second resonant circuit is connected to the high potential of the first resonant circuit. The first resonant circuit and the second resonant circuit are configured to be electrically connected to the side, and the first resonant circuit and the second resonant circuit are configured so that magnetic coupling occurs, and this magnetic coupling is performed with a coupling coefficient of about 0.2 to 0.3. A filter device characterized by: