JPH0555869A - Microwave feeding circuit - Google Patents

Abstract

PURPOSE:To reduce radio waves generated by the piezo-electric effect of a chip capacitor and to obtain a microwave feeding circuit reduced at its noise by fixing the chip capacitor to a base so as to cover it with a non-conductive resin. CONSTITUTION:Since the chip capacitor 9 is connected to a strip conductor 6 in series, only a microwave out of radio waves propagated along the conductor 6 is transmitted. On the other hand, a DC current such as a control signal and low frequency radio waves are interrupted. When a microwave is inputted to the microwave feeding circuit, the capacitor 9 made of ceramics is deformed due to an electric distortion effect included in the ceramics and mechanically oscillated. However the rigidity of the capacitor 9 is improved by epoxy group adhesives 11 and the capacitor 9 is pressed from its periphery, an oscillation suppressing effect is generated and oscillation amplitude can be reduced. Thereby the power of low frequency radio waves generated by the piezo-electric effect included in the ceramics can also be reduced and the noise-reduced microwave feeding circuit can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to reducing the noise of a microwave power feeding circuit for satellite communication, terrestrial communication, etc. which shares transmission and reception.

[0002]

2. Description of the Related Art As a conventional example of this type of microwave power feeding circuit, for example, there is a "thin power feeding circuit for a vehicle-mounted planar phased array antenna" published in C-791 of the 1989 IEICE Spring National Convention. There is a configuration example of a microwave feeding circuit configured by the strip line shown. FIG. 7 is an explanatory diagram of an antenna device incorporating a conventional microwave feeding circuit, where 1 is a transmitter, 2 is a demultiplexer, and 3
Is a conventional microwave feeding circuit including a phase shifter, 4 is an antenna element, and 5 is a receiver.

8A and 8B are views showing a structure in which a part of a conventional microwave feeding circuit incorporated in the antenna element shown in FIG. 7 is taken out. FIG. 8A is a perspective view and FIG. 8B is a side view. Is. In the figure, 6 is a strip conductor, 7 is a ground conductor plate, 8 is a dielectric substrate, 9 is a chip capacitor, and 10 is a conductive adhesive. The strip conductor 6 and the ground conductor plate 7 are provided on the surfaces of the dielectric substrate 8 that face each other, and form a microstrip line. A gap is provided in the strip conductor 6, and a chip capacitor 9 is connected with a conductive adhesive 10. The same applies when soldering is used instead of connecting with the conductive adhesive 10.

Next, the operation will be described. In the antenna element shown in FIG. 7, the microwave generated from the transmitter 1 is input to the microwave feeding circuit 3 via the demultiplexer 2 and is radiated into space from the antenna element 4. On the other hand, the incident wave to the antenna element 4 is input to the microwave power feeding circuit 3, is sent to the receiver 4 via the demultiplexer 2. here,
The microwave feeding circuit 3 is provided with a large number of phase shifters in order to control the phase shift of radio waves radiated from the antenna element 4 into space and direct the beam in a desired direction. Since it is necessary to separate the generated control signal for each phase shifter, a chip capacitor is attached to the microwave feeding circuit 3 in series with the transmission line.

FIG. 8 shows a part of the microwave power feeding circuit shown in FIG. 7 to which a chip capacitor is attached. By providing a gap in the strip conductor 6 and mounting the chip capacitor 9 with a conductive adhesive 10, It is possible to transmit only the wave and cut off the direct current such as the control signal of the phase shifter of the microwave feeding circuit incorporated in the antenna device shown in FIG. 7.

[0006]

The conventional microwave feeding circuit is constructed as described above. In the antenna device shown in FIG. 7, when a high-power microwave is input from the transmitter 1, a large current flows through the chip capacitor 9 of the microwave feeding circuit shown in FIG. For example, when the characteristic impedance of the microstrip line composed of the strip conductor 6, the ground conductor plate 7, and the dielectric substrate 8 is 50Ω, when a microwave of power 10 W is input, the chip capacitor 9 receives about 0.6 A. An electric current flows. Then, the microwave current causes the chip capacitor 9 to mechanically vibrate, and a piezoelectric effect generates a low-frequency radio wave determined by the material and structure of the chip capacitor 9. This radio wave can be detected by providing a minute loop antenna on the chip capacitor 9 and measuring the electric power excited in the minute loop antenna. An example thereof is shown in FIG. FIG. 9 shows the electric wave generated from the chip capacitor 9 into which the microwave is input, measured by the spectrum analyzer connected to the minute loop antenna. Unwanted radio waves generated from the chip capacitor 9 have a relatively low frequency of 5 to 6 MHz, but in the antenna device shown in FIG. 7, a non-linear element such as a semiconductor forming a phase shifter provided in the microwave feeding circuit 3 is used. Is cross-modulated by and appears as noise in the microwave frequency band. Part of this noise is reflected by the microwave feeding circuit 3 and the antenna element 4, is sent to the receiver 5 via the demultiplexer 2, and appears in the reception frequency band.

The present invention has been made to solve the above problems, and an object thereof is to reduce a radio wave generated by the piezoelectric effect of a chip capacitor and to obtain a low noise microwave feeding circuit.

[0008]

According to a first aspect of the microwave power feeding circuit of the present invention, a substrate on which a strip conductor serving as an input path from a transmitter is formed, a chip capacitor connected to the input path of the substrate, and a non-linear circuit In a microwave power supply circuit having an element and sharing both transmission and reception, the chip capacitor is covered and fixed to the substrate with a non-conductive resin to reduce vibration due to electric strain due to microwave input from the transmitter. It is a thing.

According to another aspect of the microwave feeding circuit of the present invention, there is provided a substrate on which a strip conductor serving as an input path from the transmitter is formed, a chip capacitor connected to the input path of the substrate, and a non-linear element. In a microwave power supply circuit that shares both transmission and reception, attach a certain weight of substance to the chip capacitor, sandwich the chip capacitor between the substance and the substrate, and distort due to microwave input from the transmitter. The vibration due to is reduced.

According to another aspect of the microwave feeding circuit of the present invention, there is provided a substrate on which a strip conductor serving as an input path from the transmitter is formed, a chip capacitor connected to the input path of the substrate, and a non-linear element. In a microwave power feeding circuit that shares transmission and reception, at least a portion of the input path from the transmitter to which the chip capacitor is connected is branched into a plurality of paths, and chip capacitors are connected to the respective paths, and the plurality of chips are connected. The capacitor is integrally fixed with a non-conductive resin.

[0011]

According to the first aspect of the invention, since the chip capacitor is covered with the non-conductive resin and fixed to the substrate, the rigidity can be increased and the vibration due to the electric strain due to the microwave input from the transmitter can be reduced.

According to the second aspect of the present invention, a substance having a predetermined weight is attached to the chip capacitor, and the chip capacitor is sandwiched between the substance and the substrate. Vibration due to electric strain due to microwave input is reduced.

According to the third aspect of the present invention, at least a portion of the input path from the transmitter to which the chip capacitors are connected is branched into a plurality of paths, the chip capacitors are connected to the respective paths, and the plurality of chip capacitors are not connected. Since it is integrally fixed with the conductive resin, the rigidity is increased and the current flowing to each chip capacitor is reduced by the microwave input from the transmitter, and the vibration due to the electric strain due to the microwave input from the transmitter is reduced.

[0014]

EXAMPLES Example 1. FIG. 1 is a perspective view showing an embodiment of the present invention, and is a configuration diagram showing a portion where a chip capacitor is connected to a strip conductor of a microwave feeding circuit. In the figure, 11 is an epoxy adhesive, and 6 to 10 are the same as those in the conventional microwave feeding circuit shown in FIG. Here, the strip conductor 6 and the ground conductor plate 7
Are provided on the surfaces of the dielectric substrate 8 that face each other, and form microstrip lines. Strip conductor 6
Is provided with a gap, in which the chip capacitor 9 is connected with the conductive adhesive 10 as in the conventional example, and the chip capacitor 9 is covered with the non-conductive resin epoxy adhesive 11 on the dielectric substrate 8. It is fixed firmly.

In the microwave feeding circuit in which the chip capacitor 9 is connected to the strip conductor 6 as described above, since the chip capacitor 9 is provided in series with the strip conductor 6, the radio wave propagated along the strip conductor 6 Among them, only microwaves are transmitted, and direct currents such as control signals and low frequency radio waves are blocked. Here, when a microwave is input to the microwave feeding circuit, the ceramic chip capacitor 9 is deformed and mechanically vibrates due to the electric strain effect of the ceramic, but the epoxy adhesive 11 increases the rigidity and the surroundings. Since it is compressed by the vibration suppression effect, the amplitude of vibration is reduced. Therefore, the electric power of the low frequency radio wave generated by the piezoelectric effect of the ceramic is also reduced. As a result, when a non-linear element such as a semiconductor is connected, it is possible to reduce the level of noise that is intermodulated by the non-linear element and appears in the microwave frequency band.

Next, the effects of the above embodiment will be verified by experiments. FIG. 2 is a configuration diagram of an experimental measurement system, and FIGS. 3 and 4 are diagrams showing measurement results. In the measurement system of FIG. 2, a diode is provided as a non-linear element in the microwave feeding circuit, the microwave input from the input terminal is added to the chip capacitor, and before and after the chip capacitor is covered with the epoxy adhesive and fixed to the dielectric substrate. The noise appearing in the reception frequency band due to the intermodulation by the diode was measured with a spectrum analyzer. 3 and 4, the type of epoxy adhesive used and the nonlinearity of the diode are different. In FIG. 3 and FIG. 4, (a) is a measurement result before fixation,
(B) shows the measurement results after fixation. In both the measurement results of FIG. 3 and FIG. 4, the noise level is 1 after sticking.
It can be seen that the noise level is reduced by about 0 dB and that the noise level is reduced by covering and fixing the chip capacitor on the dielectric substrate with the epoxy adhesive.

In the above embodiments, the epoxy-based adhesive has been described, but it goes without saying that an adhesive of another component is also effective as long as it is a non-conductive resin that covers the chip capacitor and adheres to the substrate.

Example 2. FIG. 5 is a sectional view showing another embodiment of the present invention, which is a configuration diagram showing a portion where a chip capacitor is connected to a strip conductor of a microwave power feeding circuit. In the figure, 12 is a dielectric block, 13 is an epoxy adhesive which is a non-conductive resin for mounting the dielectric block 12 on the chip capacitor 9, and 6 to 10 are those in the conventional microwave power supply circuit shown in FIG. Is the same as.

The strip conductors 6 and the ground conductor plate 7 are provided on the surfaces of the dielectric substrate 8 which face each other, and form a microstrip line. Also, the strip conductor 6
Is provided with a gap, a chip capacitor 9 is attached with a conductive adhesive 10, and a dielectric block 12 is attached to the chip capacitor 9 with an epoxy adhesive 13. In this way, the chip capacitor 9
Are sandwiched between the dielectric block 12 and the dielectric substrate 8.

In the above embodiment, when microwaves are input, the ceramic chip capacitor 9 mechanically vibrates similarly to the first embodiment, but the dielectric block 12 is attached to the chip capacitor 9 and Block 12
Since it is sandwiched between and the dielectric substrate 8, the amplitude of mechanical vibration is reduced. Therefore, the electric power of the low frequency radio wave generated by the piezoelectric effect of the ceramic is also reduced. As a result, when a non-linear element such as a semiconductor is connected, it is possible to reduce the level of noise that is intermodulated by the non-linear element and appears in the microwave frequency band.

In the above embodiment, the example in which the dielectric block is attached to the chip capacitor is shown. However, if a substance having a predetermined weight is used, a dielectric block having another shape may be used, or a dielectric block may be used for insulation. It goes without saying that it is effective even if such items are attached.

Embodiment 3. FIG. 6 is a perspective view showing still another embodiment of the present invention, and is a configuration diagram showing a portion where a chip capacitor is connected to a strip conductor of a microwave feeding circuit. In the figure, 6 to 11 are the same as those in the first embodiment shown in FIG. In this embodiment, the strip conductor 6 and the ground conductor plate 7 are provided on the surfaces of the dielectric substrate 8 that face each other, and form a microstrip line. Further, a gap is provided in the strip conductor 6 at the portion to which the chip capacitor is connected, and the strip conductor 6 is branched into three paths, and the chip capacitors 9a, 9b, 9 are provided in the respective paths.
c is connected in parallel with a conductive adhesive 10, and the chip capacitors 9a, 9b and 9c are integrally fixed with an epoxy adhesive 11 which is a non-conductive resin.

In the above embodiment, when microwaves are input, the ceramic chip capacitors 9a to 9c mechanically vibrate as in the first embodiment, but the current is distributed to the plurality of chip capacitors 9a to 9c. Therefore, the current per chip capacitor 9a to 9c decreases, and the amplitude of vibration decreases. Further, since the chip capacitors 9a, 9b, 9c are integrally fixed by the epoxy adhesive 11, the rigidity is increased by the epoxy adhesive 11 and the pressure is applied from the surroundings, so that the vibration damping effect is generated and the vibration is generated. Becomes smaller. Therefore, it is possible to reduce the electric power of the low frequency radio wave generated by the piezoelectric effect of the ceramic. As a result, when a non-linear element such as a semiconductor is connected, it is possible to reduce the level of noise that is intermodulated by the non-linear element and appears in the microwave frequency band.

Although the above-described Examples 1 to 3 show the case where the strip conductor 6 constitutes the microstrip line together with the ground conductor plate 7, other types such as a triplate type strip line and a suspended line are used. It goes without saying that it is also effective on railroad tracks. Further, although the case where the chip capacitor 9 is connected to the strip conductor 6 with the conductive adhesive 10 is shown, it is needless to say that the connection is also effective by soldering. Further, it goes without saying that the present invention can be applied to the chip resistor as in the case of the chip capacitor.

[0025]

According to the first aspect of the present invention, since the chip capacitor is covered with the non-conductive resin and adhered to the substrate to increase the rigidity, it is possible to reduce the vibration due to the electric strain due to the microwave input from the transmitter. In a microwave power feeding circuit that suppresses the generation of low-frequency radio waves from the chip capacitor and uses both transmission and reception, there is an effect that noise appearing in the reception frequency band can be reduced by intermodulation by a non-linear element.

According to the second aspect of the present invention, a substance having a predetermined weight is mounted on the chip capacitor, and the chip capacitor is sandwiched between the substance and the substrate. Therefore, the electric strain due to the microwave input from the transmitter is applied. Vibration due to
In a microwave power feeding circuit that suppresses the generation of low-frequency radio waves from the chip capacitor and uses both transmission and reception, there is an effect that noise appearing in the reception frequency band can be reduced by intermodulation by a non-linear element.

According to the third aspect of the present invention, at least a portion of the input path from the transmitter to which the chip capacitors are connected is branched into a plurality of paths, and the chip capacitors are connected to the respective paths. Since it is integrally fixed with a non-conductive resin, the rigidity can be increased and the current flowing to each chip capacitor due to the microwave input from the transmitter can be reduced, and the vibration due to the electric strain due to the microwave input from the transmitter can be reduced. In the microwave feeding circuit that suppresses the generation of low-frequency radio waves from the chip capacitor and uses both transmission and reception, there is an effect that noise appearing in the reception frequency band can be reduced by the cross modulation by the non-linear element.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention.

FIG. 2 is a configuration diagram of an experimental measurement system for demonstrating the effects of the first embodiment of the present invention.

FIG. 3 is a diagram showing measurement results demonstrating the effects of Example 1 of the present invention.

FIG. 4 is a diagram showing measurement results demonstrating the effects of Example 1 of the present invention.

FIG. 5 is a sectional view showing Embodiment 2 of the present invention.

FIG. 6 is a perspective view showing a third embodiment of the present invention.

FIG. 7 is an explanatory diagram showing an antenna element incorporating a conventional microwave feeding circuit.

FIG. 8 is a configuration diagram showing a conventional microwave feeding circuit.

FIG. 9 is a diagram showing a measurement result of unnecessary radio waves generated from a chip capacitor of a conventional microwave feeding circuit.

[Explanation of symbols]

 1 transmitter 2 demultiplexer 3 microwave feeding circuit 4 antenna element 5 receiver 6 strip conductor 7 ground conductor plate 8 dielectric substrate 9 chip capacitor 10 conductive adhesive 11 epoxy adhesive 12 dielectric block 13 epoxy adhesive Agent

Claims (3)

[Claims] 1. A microwave having a substrate on which a strip conductor serving as an input path from a transmitter is formed, a chip capacitor connected to the input path of the substrate, and a non-linear element, and sharing transmission and reception. In a power feeding circuit, the chip capacitor is covered and fixed to the substrate with a non-conductive resin to reduce vibration due to electric distortion due to microwave input from a transmitter. 2. A microwave which has a substrate on which a strip conductor serving as an input path from a transmitter is formed, a chip capacitor connected to the input path of the substrate, and a non-linear element, and which shares transmission and reception. In the power supply circuit, a substance having a predetermined weight is attached to the chip capacitor, the chip capacitor is sandwiched between the substance and the substrate, and vibration due to electric strain due to microwave input from the transmitter is reduced. And microwave feeding circuit. 3. A microwave which has a substrate on which a strip conductor serving as an input path from a transmitter is formed, a chip capacitor connected to the input path of the substrate, and a non-linear element, and which shares transmission and reception. In the power feeding circuit, at least the part of the input path from the transmitter to which the chip capacitor is connected is branched into a plurality of paths, the chip capacitors are connected to the respective paths, and the plurality of chip capacitors are integrated with a non-conductive resin. A microwave feeding circuit characterized in that it is fixed to.