JPH01252002A - Microstrip antenna - Google Patents

Abstract

PURPOSE:To obtain a compact and light microstrip antenna and to execute the transmission and reception of plural frequencies with low loss by causing the plural slots of a ground conductor board to be respectively different in a length-wise direction and stereoscopically crossing respective microstrip conductors and the respective slots. CONSTITUTION:Two microstrip lines are respectively formed by microstrip conductors 2a and 2b and a ground conductor board 3 and the two microstrip antennas are respectively formed by slots 6a and 6b of the conductor board 3 and a microstrip patch conductor 5. The slots 6a and 6b are formed in a part to be just under the conductor 5 and the conductors 2a and 2b are stereoscopically crossed with the central part of the slots 6a and 6b. Then, the lengths of the slots 6a and 6b are made difference mutually. As a result, the resonance frequencies of the respective microstrip antennas are different and the respective antennas can be used as the antennas whose transmitting frequencies are mutually different.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a microstrip antenna that can transmit and receive signals at multiple frequencies.

[Prior Art] In recent years, in mobile satellite communication systems, small and lightweight land antennas installed on moving bodies such as cars are used to perform wide-angle and high-speed beam scanning for transmitting and receiving while tracking satellites. There is a need for a high performance and highly functional antenna that can transmit and receive signals at different frequencies.

FIG. 2(A) is a plan view of the first conventional example of a microstrip antenna used in the above-mentioned mobile satellite communication system, and FIG. 2(B) is a plan view of the microstrip antenna in FIG.
Figures 2 (A) and (B) are longitudinal sectional views taken along line -B'.
), a disc-shaped reception conductor plate 23 is formed on a dielectric substrate 22 on which a ground conductor plate 21 is formed on the back surface, and a disc-shaped dielectric plate 24 is formed on the reception conductor plate 23. .

A disk-shaped transmission conductor plate 25 is formed on the dielectric plate 24 . At a position on a circle centered on the center O of the transmitting conductor plate 25 and having a radius approximately half the radius of the transmitting conductor plate 25, the transmitting conductor plate 25 and the receiving conductor plate 23 extend over 360 degrees every 30 degrees. , and the ground conductor plate 21 are connected together, and the conductor plates 21, 23, 25 and the dielectric plate 24.
, 22 through 12 earthing bins 26a to 2.
6 hours are provided.

A transmitting conductor plate 25 is insulated from the receiving conductor plate 23 and is located approximately midway between the center O of the transmitting conductor plate 25 and the earth bin 26d.
and the pin 27 connecting the center conductor 31a of the connector 30a.
a is provided, and the center conductor 3 of the receiving conductor plate 23 and the connector 30b is located on the extension line of the center O on the transmitting conductor plate 25 and the earth bin 26j and outside the earth bin 26j.
, b is provided.

Here, the connectors 30a and 30b are respectively configured by center conductors 31a and 31b, ground conductors 32a and 32b, and dielectrics 33a and 33b that insulate the center conductors 31a, 3], b and the ground conductors 32g and 32b, Ground conductor 3
2a and 32b are each connected to the ground conductor plate 21.

With the above configuration, the transmitting conductor plate 25 and the grounding conductor plate 21 operate as a transmitting microstrip antenna, while the receiving conductor plate 23 and the grounding conductor plate 21 operate as a receiving microstrip antenna. Therefore, the earth bins 26a to 26h are the transmission microstrips.

The microstrip antenna is provided to provide isolation between the microstrip antenna and the receiving microstrip antenna.

FIG. 3 is a perspective view of a second conventional one-element circular microstrip patch antenna 34 and a diplexer 35 used in the above-mentioned mobile satellite communication system.

In FIG. 3, microstrip patch antenna 3
5 is composed of a dielectric substrate 36 and a disk-shaped conductor plate 37 formed on the dielectric substrate 36. The diplexer 35 is a well-known diplexer used in a system that has different transmission and reception frequencies and simultaneously performs transmission and reception using one antenna. The diplexer 35 outputs the transmission signal input to the transmission connector 38 only to the antenna connector 40, and outputs the reception signal input to the antenna connector 40 only to the reception connector 39. Therefore, the transmit connector 38 and the receive connector 39
The transmission frequency and the reception frequency are electrically isolated from each other.

The center conductor of the antenna connector 40 of the diplexer 35 is connected to a power feeding point 37g on the outer periphery on the back surface of the conductive plate 37 via a lead wire 41 that penetrates the dielectric substrate 36 while being insulated from the dielectric substrate 36. Ru.

With the above configuration, the transmission signal input to the transmission connector 38 is output to the microstrip patch antenna 34 via the diplexer 35 and transmitted, while the reception signal received at the microstrip patch antenna 34 is transmitted. It is output to the reception connector 39 via the diplexer 35.

Conventionally, when beam scanning is performed using the antennas of the first and second conventional examples described above, a plurality of the antennas are arranged in an array, and a high-output power amplifier and a transmitter are connected to the transmission connectors of the antennas. A transmitter is connected via a phase shifter, and a receiver is connected to the receiving connector of the antenna via a low noise amplifier and a receiving phase shifter, and the transmitting phase shifter and receiving phase shifter are connected to the receiving connector of the antenna. control each phase shift amount.

[Problems to be Solved by the Invention] In the antenna of the first conventional example described above, the structure is complicated because it is necessary to provide the earth bins 26a to 26h and the bins 27a and 27b, and therefore the manufacturing process is complicated. Therefore, the manufacturing cost is relatively high. In addition, a low noise amplifier is connected to connectors 3Qa and 30b via cables.
Since the high-power amplifier, phase shifter, transmitter, and receiver are connected, transmission loss becomes relatively high, and the size of the system including these devices and antennas becomes large.

In addition, in the second conventional example described above, since the insertion loss of the guiplexer for separating the transmitted and received signals is generally about 2 to 3 dB, the carrier signal power to noise power ratio (hereinafter referred to as CN ratio) of the received signal is approximately 2 to 3 dB. ) will be significantly deteriorated. Also, like the first conventional example, the connector 38.3
Since the low-noise amplifier, high-power amplifier, phase shifter, transmitter, and receiver are connected to the There was a problem that the shape became large.

An object of the present invention is to solve the above problems and provide a microstrip antenna that is smaller and lighter than conventional examples, has low transmission loss, and can transmit and receive signals of multiple frequencies. .

[Means for Solving the Problems] The present invention provides a microstrip patch conductor formed on one surface of a first dielectric substrate, and a microstrip patch conductor formed on the other surface of the first dielectric substrate. a ground conductor plate, and a conductor plate formed on the ground conductor plate directly below the microstrip patch conductor in a radial shape from a predetermined reference point on the ground conductor plate and penetrating the ground conductor plate, respectively in the longitudinal direction. A plurality of slots having different lengths, a second dielectric substrate formed on the surface of the ground conductor plate opposite to the surface on which the first dielectric substrate is formed, and the ground conductor plate formed A plurality of microstrip conductors are formed on the surface of the second dielectric substrate opposite to the surface where the microstrips are formed so as to intersect with the plurality of slots three-dimensionally.

[Function] With the above configuration, the microstrip patch conductor and the plurality of slots formed in the ground conductor plate each constitute a plurality of microstrip antennas, while the plurality of microstrip conductors A plurality of microstrip lines are formed by the ground conductor plate and the ground conductor plate. Here, since the plurality of slots have different lengths in the longitudinal direction, the plurality of microstrip antennas have different resonant frequencies. Furthermore, since each of the microstrip conductors is formed to three-dimensionally intersect with each of the slots, a plurality of signals having different frequencies input to the plurality of microstrip lines can be transmitted to the plurality of microstrip antennas. Excite. Therefore, the plurality of signals are respectively radiated from the plurality of microstrip antennas. Similarly, signals having different frequencies can be received by the plurality of microstrip antennas.

[Embodiment 1 First Embodiment FIG. 1(A) is an exploded perspective view of a microstrip antenna according to a first embodiment of the present invention, and FIG. 1(B) is an exploded perspective view of the microstrip antenna of FIG. 1. The plan view of FIG. 1(C) is a longitudinal cross-sectional view taken along the line A-A" of FIG. 1(B).

In the microstrip antenna of this embodiment, two
It is characterized by comprising two microstrip conductors 2a+2b and two slots N3a and 6b formed in the ground conductor plate 3.

In Figure 1 (A), (B), and (C), the dielectric constant is 8
microstrip conductors 2a, 2 each having a width of
b are formed parallel to each other. Here, the microstrip conductors 2a and 2b each have an end portion 2 aal 2
ab, end 2 ha, 2 bb, end 2 aal
2 ba is located at the outer periphery of the dielectric substrate 1 . A ground conductor plate 3 having the same planar shape as the dielectric substrate l is formed on the dielectric substrate 1, and a dielectric conductor plate 3 having the same planar shape as the dielectric substrate 1 and the ground conductor plate 3 is formed on the ground conductor plate 3. rate εr,
A dielectric substrate 4 having a thickness d and a thickness d is formed. A disk-shaped microstrip patch conductor 5 with a radius r is formed on the center portion of the dielectric substrate 4.

Slots 6a and 6b are formed in the ground conductor plate 3, penetrating from the upper surface to the lower surface of the ground conductor plate 3. The planar shape of the slot 6a is a rectangle having a width a and a length O in the longitudinal direction. The planar shape of the slot 6b is a width a and a length 12. It has a rectangular shape with a length Q in the longitudinal direction that is different from . Here, both the slots 6a and 6b are directly below the microstrip patch conductor 5, and the extension line extending from the longitudinal center line passing through the widthwise centers of the slots 6a and 6b is the microstrip patch conductor 5. It is formed so as to pass through the center O of the conductor 5. Further, the microstrip conductors 2a and 2b are respectively shown in FIG. 1(B).
In the plan view of the slots 6a and 6b, the slots 6a and 6b intersect with each other, that is, intersect with each other in a three-dimensional manner, and the slots h6a,
6b, each protrudes by a length s I+ s .

With the above configuration, the microstrip conductor 2a and the ground conductor plate 3 form a first microstrip line, while the microstrip conductor 2b and the ground conductor plate 3 form a second microstrip line. ing. Also, the slot formed in the ground conductor plate 3)
5a and the microstrip patch conductor 5 form a first microstrip antenna, while the slot 6b formed in the ground conductor plate 3 and the microstrip patch conductor 5 form a second microstrip antenna. Therefore, for example, microstrip conductor 2
By connecting a transmitter to the end 2aa of the microstrip conductor 2a and the end 2ba of the microstrip conductor 2b, and inputting the first and second transmission signals to the first and second microstrip lines, A first microstrip antenna is inputted via a first microstrip line.
excited by a transmission signal, a first transmission signal is radiated from the first microstrip antenna, and
The second microstrip antenna is excited by the second transmission signal input via the second microstrip line, and the second transmission signal is radiated from the second microstrip antenna. Here, since the lengths of the slots 6a and the slots 6b are different from each other, as is known, the resonance frequencies of the first and second microstrip antennas are different, and the first and second microstrip antennas are connected to each other. It can be used as an antenna with different transmission frequencies. Further, one or the other of the first and second microstrip antennas may be used as a transmitting antenna and a receiving antenna, respectively, or both the first and second microstrip antennas may be used as a receiving antenna. It may also be used as

As is well known, by changing the lengths Sl and St of the microstrip conductors 2a and 2b, the reactance of the antenna impedance of the first and second microstrip antennas is changed, respectively. Therefore, the lengths Sl and S2 match the characteristic impedance of the first microstrip line and the antenna impedance of the first microstrip antenna, and match the characteristic impedance of the second microstrip line and the antenna impedance of the second microstrip line, respectively. The antenna impedances of the strip antennas are set to match.

As explained above, the first and second microstrip antennas having different resonance frequencies are integrally formed, and the first and second microstrip lines are directly connected to the first and second microstrip antennas, respectively. Since they are connected, it is possible to realize a microstrip antenna that is smaller and lighter than conventional examples, has lower transmission loss, and can transmit and receive signals at two frequencies.

Second Embodiment FIG. 4 is a plan view of a microstrip antenna which is a second embodiment of the present invention.
) or C) are given the same reference numerals.

The microstrip antenna of this second embodiment is
What is different from the embodiment is that the slots 6a and 6b and the microstrip conductors are arranged so that the long sides of the slots a and 6b and the long directions of the microstrip conductors 2a and 2b are perpendicular to each other. 2a and 2
b.

The microstrip antenna configured as described above has the same functions and effects as the microstrip of the first embodiment described above, and since the slots 6a and 6b are provided at right angles to each other, This embodiment has a unique effect in that it is possible to obtain a larger amount of mutual coupling between the first and second microstrip antennas than in the first embodiment.

Experimental Example In this experimental example, the first and second microstrip antennas are viewed from the first and second microstrip lines, respectively, using the microstrip antenna of the second embodiment shown in FIG. The reflection loss ffi[d
B] and the amount of mutual coupling [dB] between the first and second microstrip antennas from the first and second microstrip lines. That is, the first and second
A signal having a predetermined level and a frequency range from IGHz to 2GHz is inputted to the first and second microstrip antennas through the microstrip lines of the first and second microstrip lines, respectively. The level of the reflected signal reflected and output via the first and second microstrip lines is measured, and the input signal level [d B ] is calculated from the reflected signal level [d B ].
] and the amount of mutual coupling [dB] between the first and second microstrip antennas were determined.

Note that the widths of the microstrip conductors 2a and 2b were set so that the characteristic impedance of the first and second microstrip lines was 50Ω.

Both the dielectric constant εrl of the dielectric substrate l and the dielectric constant εr of the dielectric substrate 4, each having a square shape of 150 mm square, are 2.
．． 55, the thickness dl of the dielectric substrate 1 and the dielectric substrate 4
The thickness d was set to 1.6 mm and 0°81, respectively.

Also, the radius r of the microstrip patch conductor 5 is 31
Near mm, each length of slot) 6a and 6b &, 1
2. were set to 21 mn+ and 14 mm, respectively. Further, the width of the slots 6a and 6b is 1.5 mm, and the distance from the end of each slot 5a, 3b on the center O side to the center O is 10 mm.

It was set to 17 mm.

FIG. 6(A) is a graph showing the frequency characteristics of the first and second microstrip antennas of the second embodiment with respective return losses of 101° and 102, and FIG. 6(B) is a graph showing the frequency characteristics of the first and second microstrip antennas of the second embodiment. It is a graph showing the frequency characteristic of mutual coupling ffi [dB] between the first and second microstrip antennas of the example.

As shown in FIG. 6(A), the first and second microstrip antennas are in a resonant state at frequencies of about 1550 MHz and about 1650 MHz, respectively, and the amount of return loss for the first microstrip antenna in the first microstrip line is is frequency 1550MHz
The reflection loss amount for the second microstrip antenna in the second microstrip line is -3 at a frequency of 1650MHz.
It is 0 [dB]. Furthermore, as shown in FIG. 6(B), the amount of mutual coupling between the first and second microstrip antennas at a frequency of 1550 MHz is 14.5.
[dB], and the amount of mutual coupling between the first and second microstrip antennas at a frequency of 1650 MHz is 35 [dB]. In addition, the above frequency 1650
MH2 is an uplink frequency used in an L frequency band mobile satellite communication system such as Inmarsat, and a frequency of 1550 MHz is a downlink frequency used in the above mobile satellite communication system.

Therefore, this experimental example shows that sufficient isolation can be achieved between the first microstrip antenna and the second microstrip antenna, and the microstrip antenna of the second example is used at two frequencies. It shows that it is possible.

Third Embodiment FIG. 5 is a plan view of a microstrip antenna which is a third embodiment of the present invention.
) or C) are given the same reference numerals.

The microstrip antenna of this embodiment differs from the microstrip antenna of the first embodiment in that it is provided with eight slots 6a to 6h and eight microstrip conductors 2a to 2h.

In FIG. 5, slots 6a to 6h passing through the ground conductor plate 3 in the thickness direction are formed in the ground conductor plate 3, and the planar shapes of the slots 6a to 6h are respectively a width a and a width a.
Each has a rectangular shape with different lengths θ to Q8 in the longitudinal direction. In addition, microstrip conductors 2a to 2h each having a width are formed on the back surface of the dielectric substrate 1.

Here, each of the slots 6a to 6h is directly below the microstrip patch conductor 5, and the slots 6a to 6h are
The extended line extending from the longitudinal center line passing through the widthwise centers of a to 6h is the microstrip patch conductor 5.
The slot 6 is formed so as to pass through the center O of the slot 6.
The slots a to 6h are respectively formed at positions where adjacent slots are at an angle of 30 degrees with respect to the center O, that is, as shown in FIG. 5, they are formed in a radial shape with the center O as the center. Furthermore, the microstrip conductor 2a
In the plan view of FIG. 5, the slots 6a to 2h intersect with the approximate centers of the slots 6a to 6h, that is, intersect three-dimensionally, and have lengths S and S, respectively, from the intersections with the slots 6a to 6h. , very prominent. Further, on the opposite side of the protruding side of the microstrip conductors 2a to 2h, the microstrip conductors 2a to 2h are bent at a predetermined angle after intersecting with the slots 6a to 6h, respectively. Further, the microstrip conductors 2a to 2h are arranged so that the angle between the longitudinal sides of the microstrip conductors 2a to 2h and each side of the dielectric substrate 1 is a right angle at the outer periphery of each side of the dielectric substrate 1. is formed.

By configuring as described above, the microstrip conductors 2a to 2h and the ground conductor plate 3 each provide the first
to form an eighth microstrip line, and
The slots 6a to 6h formed in the ground conductor plate 3 and the microstrip patch conductor 5 form first to eighth microstrip antennas, respectively. Here, each length I21 to g of slot) 6a to 6h
As is known, the first to eighth microstrip antennas can be used as antennas having different resonance frequencies, and each of the eight microstrip antennas can be used as a transmitting antenna or as a receiving antenna. It can be used as an antenna.

As is well known, by changing the lengths S to S8 of the microstrip conductors 2a to 2h, the antenna impedance and actance of the first to eighth microstrip antennas are changed, respectively. Therefore, the length S.

to Sll are respectively set so that the characteristic impedance of the first to eighth microstrip lines matches the antenna impedance of the first to eighth microstrip antennas, respectively.

As explained above, the first to eighth microstrip antennas having different resonance frequencies are integrally formed, and the first to eighth microstrip lines are directly connected to the first to eighth microstrip antennas, respectively. Since the microstrip antennas are connected, it is possible to realize a microstrip antenna that is smaller and lighter than the conventional example, has low transmission loss, and can transmit and receive signals at eight frequencies.

In the first to third embodiments described above, the microstrip conductors 2a to 2h are shown in FIG. 1(B), respectively.
Although it intersects with the approximate center of the slots 6a to 6h in the plan views of FIGS. 4 and 5, the present invention is not limited to this.
The microstrip conductors 2a to 2h are formed to intersect at least a portion of the slots 6a to 6h in the plan views of FIGS. 1(B), 4, and 5, respectively, so as to provide so-called offset power feeding. You may also do so.

In the first to third embodiments described above, the microstrip conductor 5 is formed in the shape of a disk, but the microstrip conductor 5 is not limited to this, and the microstrip conductor 5 has a rectangular or square shape. Other plate shapes may also be used.

In the first to third embodiments described above, microstrip antennas capable of transmitting and receiving signals at two frequencies, two frequencies, and eight frequencies are described, respectively. A microstrip antenna capable of transmitting and receiving signals at a plurality of arbitrary frequencies may be configured by providing an arbitrary number of different slots 6a to 6h and microstrip conductors 2a to 2h.

Here, as described above, each slot is directly below the microstrip patch conductor 5, and the extension line extending from the longitudinal center line passing through the widthwise center of each slot is the microstrip patch conductor. 5, that is, it is formed in a radial shape around the center O as shown in FIG. By configuring as above, similarly to the first to third embodiments,
It is possible to realize a microstrip antenna that is smaller and lighter than conventional examples, has low transmission loss, and can transmit and receive signals at multiple frequencies.

In the first to third embodiments described above, microstrip antennas capable of transmitting and receiving signals at two frequencies, two frequencies, and eight frequencies are described, respectively. As shown, when beam scanning is performed using the microstrip antenna of the present invention, a plurality of the antennas are arranged in an array, and a high-output power amplifier is connected to the microstrip line connected to the transmission microstrip antenna. and a transmitter via a transmission phase shifter, and a receiver is connected to a microstrip line connected to the reception microstrip antenna via a low noise amplifier and a reception phase shifter, The configuration may be such that the amount of phase shift of each of the transmission phase shifter and the reception phase shifter is controlled. When configured in this way, functional circuits such as the high-output power amplifier, transmitting phase shifter, transmitter, low-noise amplifier, receiving phase shifter, and receiver are mounted on the back surface of the dielectric substrate 1 in a small size. Since it occupies a small area and connects each functional circuit and the microstrip antenna with a microstrip line, it is possible to integrate a system with the above functional circuits and the microstrip antenna, which is smaller and smaller than the conventional example. It has the advantage of being lightweight and can be realized with low transmission loss.

[Effects of the Invention] As described in detail above, according to the present invention, a plurality of microstrip antennas are each constituted by a microstrip patch conductor and a plurality of slots formed in a ground conductor plate, while a plurality of microstrip antennas are configured by a plurality of microstrip antennas. A plurality of microstrip lines are formed by the conductor and the ground conductor plate, and the plurality of slots are configured to have different lengths in the longitudinal direction, so that the plurality of microstrip antennas have different resonant frequencies. Furthermore, since each of the microstrip conductors is formed to three-dimensionally intersect with each of the slots, a plurality of signals having different frequencies can be transmitted and received by inputting and outputting signals to the plurality of microstrip lines. be able to.

Furthermore, when performing beam scanning using the microstrip antenna of the present invention, a plurality of the microstrip antennas described above are arranged in an array, and a high-output power amplifier is connected to the microstrip line connected to the microstrip antenna for transmission. and a transmitter via a transmission phase shifter, and a receiver is connected to a microstrip line connected to the reception microstrip antenna via a low noise amplifier and a reception phase shifter, The configuration may be such that the amount of phase shift of each of the transmission phase shifter and the reception phase shifter is controlled. When configured in this way, functional circuits such as the high output power amplifier, transmission phase shifter, transmitter, low noise amplifier, reception phase shifter, and receiver are mounted on the dielectric substrate 1.
Since it is formed with a small footprint on the back side of the back side, and each functional circuit and the microstrip antenna are connected by a microstrip line, it is possible to integrate a system with two functional circuits and a microstrip antenna. It has the advantage of being smaller and lighter than the conventional example, and can be realized with low transmission loss.

[Brief explanation of the drawing]

FIG. 1(A) is an exploded perspective view of a microstrip antenna according to the first embodiment of the present invention, FIG. 1(B) is a plan view of the microstrip antenna of FIG. 1, and FIG. 1(C) is a top view of the microstrip antenna of FIG. FIG. 1(B) is a longitudinal cross-sectional view taken along the line AA'; FIG. 12(A) is a plan view of the first conventional microstrip antenna used in a mobile satellite communication system; FIG. B) is a vertical cross-sectional view taken along the line B-B' in Figure 2 (A), and Figure 3 is a diagram of the second conventional example of a one-element circular microstrip patch antenna and a guiplexer used in a mobile satellite communication system. 4 is a plan view of a microstrip antenna that is a second embodiment of the present invention; FIG. 5 is a plan view of a microstrip antenna that is a third embodiment of the present invention; and FIG. 6 (A ) is a graph showing the frequency characteristics of the amount of return loss of the first and second microstrip antennas in the second embodiment of FIG. 4, and FIG. 3 is a graph showing the frequency characteristics of the amount of mutual coupling between the first and second microstrip antennas. 1.4...Dielectric substrate, 2a to 2h...Microstrip conductor, 3...
・Grounding conductor plate, 5...Microstrip patch conductor, 5a to 6
h...Slot. Figure 1 (A) Figure 1 (B) Figure 2 (A) Figure 2 (B) Figure 3

Claims (2)

[Claims] (1) A microstrip patch conductor formed on one surface of the first dielectric substrate, a ground conductor plate formed on the other surface of the first dielectric substrate, and the microstrip patch conductor a plurality of slots formed in the ground conductor plate directly below the ground conductor plate in a radial shape from a predetermined reference point on the ground conductor plate and penetrating the ground conductor plate, each having a different length in the longitudinal direction; a second dielectric substrate formed on a surface of the ground conductor plate opposite to the surface on which the first dielectric substrate is formed; A microstrip antenna comprising a plurality of microstrip conductors formed on a surface of a dielectric substrate so as to intersect each of the plurality of slots three-dimensionally. (2) The microstrip antenna according to claim 1, wherein the microstrip patch conductor has a disk shape or a rectangular plate shape.