JPH0581081B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention is applicable to a microwave receiver equipped with a mixing circuit that receives signals of multiple frequencies in the microwave band and converts them into the same intermediate frequency signal, such as a microwave receiver for radio location work. This invention relates to a receiving device. [Prior Art] Conventionally, a microwave receiving device for radio location service, which is an example of this type of microwave receiving device, has been configured to operate at two frequencies of the microwave band, 10.525 GHz and 24.15 GHz, which are assigned to radio location service. In order to receive the signal heterodyne, the intermediate frequency converter is configured as shown in FIG. 5, FIG. 6, or FIG. 7, for example. The intermediate frequency conversion section in FIG.
Two local oscillation circuits are connected to two mixing circuits 1 and 2 into which a 10.525 GHz received signal (hereinafter referred to as the first received signal) and a 24.15 GHz received signal (hereinafter referred to as the second received signal) are respectively input. Local oscillation frequency of the first and second received signals of 3 and 4: 10.0GHz, 23.625G
Hz oscillation signals are supplied to mixer circuits 1 and 2.
The first and second received signals are the same frequency 0.525G.
The intermediate frequency signals of both mixing circuits 1 and 2 are converted into intermediate frequency signals of Hz, and the intermediate frequency signals of both mixing circuits 1 and 2 are sent to an intermediate frequency amplifier 5.
It is output to the subsequent circuit section via. Next, the intermediate frequency conversion section in FIG.
An oscillation signal with a local oscillation frequency of 9.525 GHz from the local oscillation circuit 7 is supplied to the mixing circuit 6 into which the second received signal is input, and the mixing circuit 6 receives the first and second received signals at frequencies of 1.0 GHz and 14.625 GHz, respectively. Convert to intermediate frequency signal. Further, the mixing circuit 8 connected to the mixing circuit 6 is supplied with an oscillation signal of a local oscillation frequency of 13.625 GHz from the local oscillation circuit 9. And the frequency of mixing circuit 6 is 1.0GHz, 14.625G
The Hz intermediate frequency signal is branched into two and supplied to a first intermediate frequency amplifier 10 and a mixing circuit 8. At this time, the first intermediate frequency amplifier 10 is 1.0G
The intermediate frequency of Hz is extracted and amplified by a 1.0 GHz filter, and one primary amplified intermediate frequency signal with a frequency of 1.0 GHz is output. This primary amplified intermediate frequency signal is the frequency
This is an intermediate frequency signal of the first received signal of 10.525 GHz. In addition, the mixing circuit 8 is 13.625G of the local oscillation circuit 9.
The Hz oscillation signal converts intermediate frequency signals of 1.0 GHz and 14.625 GHz into primary amplified intermediate frequency signals of 12.625 GHz and 1.0 GHz, respectively. 1.0G of both primary amplified intermediate frequency signals
The Hz signal is the intermediate frequency signal of the second received signal. Then, the output signals of the first intermediate frequency amplifier 10 and the mixing circuit 8 are supplied to the second intermediate frequency amplifier 11, and this amplifier 11 uses a 1.0 GHz filter to pass the output signals of the first intermediate frequency amplifier 10 and the mixing circuit 8 to a frequency of 1.0 GHz. Both primary amplified intermediate frequency signals are extracted and output to the subsequent circuit section. Next, the intermediate frequency conversion section in FIG.
The mixing circuit 12 to which the second received signal is input is provided with mixer diodes D1 and D2 connected in antiparallel, and the local oscillation circuit 1
Local oscillation frequency 5.766GHz from 3 to mixing circuit 12
(= fp), and the mixing circuit 12 forms an intermediate frequency signal of the first received signal with a frequency of 1.007 GHz from the difference between the frequency of the first received signal and the double frequency 2fp of the oscillation signal, An intermediate frequency signal of the second received signal with a frequency of 1.086 GHz is formed from the difference between the frequency of the second received signal and the quadruple frequency 4fp of the oscillation signal, and both intermediate frequency signals are sent to the subsequent circuit section via the intermediate frequency amplifier 14. Output. On the other hand, for example, IEICE technical report MW78-
48 (published in 1978), pages 75 to 80, "6 to 12 GHz pass-through dielectric resonator transistor oscillator," which utilizes the resonance of a dielectric resonator based on the negative resistance characteristics of field effect transistors. The combination of microstrip line and microstrip line makes it compact and
It is described that a lightweight microwave band oscillator with good characteristics can be formed. In addition to the pass-through type dielectric resonator described in the above-mentioned IEICE technical report, there are also feedback-type and reflection-type dielectric resonators. [Problems to be Solved by the Invention] In the case of the receiving apparatus shown in FIGS. 5 and 6, in order to receive signals of two frequencies in the microwave band,
Since it is necessary to provide two mixing circuits 1, 2 or 6, 8 and two local oscillation circuits 3, 4 or 7, 9, there is a problem that the configuration becomes complicated. Further, in the case of the receiver shown in FIG. 7, the intermediate frequency converter is formed by providing only one mixing circuit 12 and one local oscillation circuit 13, but in this case, the oscillation signal of the local oscillation circuit 13 is Since this is equivalent to using a signal multiplied by 2 or 4, the level of the oscillation signal mixed with the first and second received signals decreases in proportion to the multiplication number, and the conversion loss of the mixing circuit 12 increases. There is a problem in that the level of the intermediate frequency signal of both received signals outputted from the mixing circuit 12 decreases. The present invention has a simple configuration with only one mixing circuit and one local oscillation circuit, and without increasing the conversion loss of the mixing circuit, multiple reception signals in the microwave band can be converted into the same intermediate frequency signal without level differences. The purpose is to convert. [Means for Solving the Problems] In order to achieve the above object, the microwave receiving device of the present invention converts received signals of multiple frequencies in the microwave band into intermediate frequency signals of the same frequency and outputs the same. and a local oscillation circuit that outputs an oscillation signal at the local oscillation frequency of each received signal to this mixing circuit. A coupling microstrip line is connected to the gate of the transistor, a biasing microstrip line is connected to the drain of the field effect transistor at its end, and a microstrip line is connected to the source of the field effect transistor at its end. The microstrip line for output, the microstrip line for coupling, and the microstrip line for bias are high-frequency coupled, and multiple resonant modes with different frequencies are generated due to the negative resistance characteristics of the field effect transistor. A dielectric resonator from which an oscillation signal is led out to an output microstrip line, and an oscillation signal at the local oscillation frequency of each received signal of each oscillation signal of the output microstrip line to a mixing circuit. It is formed by an output filter. [Operation] In the microwave receiving device of the present invention configured as described above, the thickness and width of the dielectric resonator are set based on the negative resistance characteristics of the field effect transistor of the local oscillation circuit. It resonates in a plurality of resonance modes with different frequencies, and the oscillation signals of each frequency in the microwave band generated by this resonance have almost the same large level. Then, the oscillation signal at the local oscillation frequency of each received signal is extracted and output from the filter to the mixing circuit. At this time, the oscillation signal at the local oscillation frequency of each extracted received signal becomes almost the same large level, With a simple configuration in which only one oscillation circuit and one mixing circuit are provided, each received signal is converted into the same intermediate frequency signal without increasing the conversion loss of the mixing circuit. [Example] An example will be described with reference to FIGS. 1 to 4. Figure 1 shows a microwave receiver for radio location work. In the figure, 15 indicates the microwave band.
A mixing circuit into which the first and second received signals of 10.525 GHz and 24.15 GHz are input, 16 is a local oscillation circuit connected to the mixing circuit 15, and the local oscillation frequencies of the first and second received signals are 13.625 GHz and 27.250 GHz. GHz oscillation signals are simultaneously output to the mixing circuit 15. 17 is an intermediate frequency amplifier connected to the mixing circuit 15, which mixes the first and second received signals and the oscillation signals of the respective local oscillation frequencies to form intermediate frequency signals of the same frequency, that is, 3.1 GHz. The intermediate frequency signal is amplified and output to the subsequent circuit section. The local oscillation circuit 16 is a feedback type dielectric resonator (not shown) shown in FIG. 3 using a cylindrical dielectric resonator 18 having a diameter D and a height L as shown in FIGS. 2a and 2b. and a broadband filter consisting of a directional coupler. In FIG. 3, 19 is a field effect transistor for microwave oscillation, 20 is a coupling microstrip line provided close to the outer periphery of the dielectric resonator 18, and one end is connected to the gate G of the transistor 19. and the other end is grounded. A bias microstrip line 21 is provided at right angles to the coupling microstrip line 20 and close to the outer periphery of the dielectric resonator 18, and one end is connected to the drain D of the transistor 19. and the other end is connected to a bias power supply. Reference numeral 22 designates an output microstrip line provided on an extension of the coupling microstrip line 20 and away from the dielectric resonator 18, one end of which is connected to the source S of the transistor 19, and the other end connected to the source S of the transistor 19. The end is grounded via a resistor 23. The drain D of the transistor 19, the microstrip line 21 for bias, the dielectric resonator 18, and the microstrip line 20 for coupling.
and the path of the gate G of the transistor 19,
A feedback circuit for oscillation is formed, and by applying a DC bias voltage to the bias microstrip line 21, the dielectric resonator 1 is activated based on the negative resistance characteristic between the gate G and source S of the transistor 19.
8 resonates in multiple resonance modes set by the diameter D, height L, etc., and the oscillation signal of each resonance mode of the dielectric resonator 18 is output to the microstrip line 2.
2 are derived simultaneously. In addition, Fig. 3 shows that the oscillation frequency fr of each resonance mode of the feedback dielectric resonator is expressed by the following Cohn equation.
x(n) in the equation represents the Bessel function Jn(x), and λ ₀ =c/fr (c is the speed of light).

〔Effect of the invention〕

Since the present invention is configured as described above, it produces the effects described below. The local oscillation circuit 16 includes a dielectric resonator 18, a field effect transistor 19, and microstrip lines 20, 21, 22 for coupling, bias, and output.
and a filter that extracts an oscillation signal at the local oscillation frequency of each received signal from the oscillation signal of each resonance mode with a different frequency derived to the output microstrip line 22. Since a high-level oscillation signal with almost the same local oscillation frequency as each received signal is output and each received signal is converted into the same intermediate frequency signal, it is simple to install only one mixing circuit and one local oscillation circuit. With this configuration, it is possible to convert received signals of different frequencies in the microwave band into intermediate frequency signals of the same frequency and the same level without increasing the conversion loss of the mixing circuit.

[Brief explanation of the drawing]

1 to 4 show one embodiment of the microwave receiving device of the present invention, FIG. 1 is a block diagram, and FIGS. 2a and 2b are plan views of a dielectric resonator provided in a local oscillation circuit. , front view, Figure 3 is a detailed wiring diagram of a part of the local oscillation circuit, Figure 4 is a frequency characteristic diagram of the oscillation signal output from the local oscillation circuit, Figures 5, 6, and 7 are FIG. 3 is a block diagram of a conventional device. 15...Mixing circuit, 16...Local oscillation circuit, 1
8...Dielectric resonator, 19...Field effect transistor, 20, 21, 22...Microstrip line for coupling, bias, and output.

Claims (1)

[Scope of Claims] 1. A mixing circuit that converts received signals of a plurality of frequencies in the microwave band into intermediate frequency signals of the same frequency and outputs the same, and an oscillation signal of a local oscillation frequency of each of the received signals to the mixing circuit. a local oscillation circuit for outputting the local oscillation circuit, the local oscillation circuit comprising a field effect transistor for microwave oscillation;
a coupling microstrip line having an end connected to the gate of the field effect transistor; a biasing microstrip line having an end connected to the drain of the field effect transistor; An output microstrip line connected to the source of the field effect transistor, and high frequency coupled to the coupling microstrip line and the bias microstrip line, and a negative polarity of the field effect transistor. a dielectric resonator in which oscillation signals in a plurality of resonant modes having different frequencies depending on resistance characteristics are guided to the output microstrip line; A microwave receiving device comprising a filter that outputs an oscillation signal at a local oscillation frequency of each received signal to the mixing circuit.