JPS60171811A - Microwave frequency converter - Google Patents

Abstract

PURPOSE:To obtain a microwave frequency converter excellent in the image disturbing characteristic with less local signal radiation by using a waveguide giving a cut-off region to a local frequency and a pressing region to an RF frequency. CONSTITUTION:The local signal is cut off and the RF signal is passed through a rectangular waveguide 22. A metallic post 23 connects the waveguide 22 and a microwave integrated circit 3. A cylindrical ''Teflon'' rod 24 is inserted to an inserting hole 25 of the metallic post so as to isolate the waveguide in terms of DC and form partially a coaxial line. A disk hole 26 is provided concentrically with the post 23, the diameter is smaller than the diameter of the insertion hole 25 and larger a little than the width of a center conductor 4 of a microstrip line. RF amplifier circuits 29, 30 are prevented to a microwave integrated circuit. A mixer circuit 31, a local oscillating circuit 32, a dielectric resonator for stable oscillation and a screw 28 for adjusting local oscillating frequency are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a microwave down converter used in satellite broadcast receivers and the like. Suburbs Ga As
With the development of microwave semiconductor devices such as FETs, microwave frequency converters have been constructed using microwave integrated circuits, etc., and SHF converters combining this with input waveguides are about to be put into practical use. In this case SHF
The converter has a local oscillation circuit for frequency conversion, but in the SHF converter, local signal radiation from this local oscillation circuit may cause interference to other microwave equipment, so it is desirable to minimize it as much as possible. At the same time, it is also required to be strong against image interference. The present invention provides a cutoff region, R
The present invention aims to provide a microwave frequency conversion device with less local signal radiation and good image disturbance characteristics by using a waveguide that exhibits a passband for the F frequency.

Conventional configuration and its problems In the wave integrated circuit (MIC circuit), 4 and 5 are its center conductor and ground groove i, and the ground conductor 5 is in contact with the inner wall of the H plane of the waveguide 1, and the waveguide Tube 1 and MIC circuit 3 are ridge waveguide 2
are connected by. The RF signal from the waveguide 1 is converted into an RF signal by the microwave frequency conversion circuit configured in the MIC circuit 3 shown in FIG. Figure 1: MIC
In the circuit 3, the RF multiplied signal from the waveguide 1 is coupled to the center conductor 4 of the MIC circuit, and the Ga
A DC blocking capacitor 1 is added to the AsFET amplifier 7.
1 and then added to the double balanced mixer circuit 12. At the same time, the GaA stabilized by the dielectric resonator 17
The oscillation output of the sFET oscillator 16 is added to the double-balanced mixer circuit, and output from the IF multiplied signal 16 as a mixed output.

Here, 9 and 18 are drain resistances, 19 is source resistance,
20 is a termination resistor, 8 and 21 are drain application voltage terminals, 10 is a gate voltage terminal, and 13° and 14 are mixer diodes. Currently, as a microwave frequency converter,
Input RF signal 12GHz band, local oscillation frequency 10.
Considering an SHF down converter in the 7 GHz, IF frequency band, one of the SHF converter's performances is radiation to the input side of the local frequency and image disturbance characteristics that must be strictly controlled for the coming satellite broadcasting era.

However, in the conventional configuration, a part of the input of the MIC circuit is inside the waveguide, so the MIC of the local oscillation output
The leakage to the input side of the circuit is as it is with 'J Tsuji 5) (
It is radiated into free space through the F antenna and becomes a disturbance. As a countermeasure to this, a bandpass filter or a local trap filter may be configured in the waveguide 1, but this causes insertion loss due to the insertion of the filter, and the N of the converter
, F2, and the waveguide length becomes considerably large due to the filter configuration, resulting in an overall large SHF converter. If you use a ridge circuit to couple the waveguide and MIC circuit, you can create a broadband Hiko waveguide-MI.
In order to obtain C circuit conversion, a large number of stages of ridge waveguides are required, which increases the overall length. Also, waveguides 1 and M
Since it is directly connected to the IC circuit 3 in terms of DC, the first stage of the MIC circuit always requires a DC blocking capacitor 6, and the insertion loss due to its insertion also reduces local signal radiation that degrades the N and F of the converter. Good image interference characteristics,
Equipped with easy-to-configure broadband waveguide-MIC circuit conversion,
The purpose of the present invention is to provide a microwave frequency conversion device that is extremely compact and highly suitable for mass production.

Structure of the Invention The present invention provides a waveguide that uses the local oscillation frequency of a microwave frequency conversion circuit as a cutoff range and has an RF band as a passband.
used for the input section and short-circuiting the other end of the waveguide,
A microwave integrated circuit is fixed on the waveguide outer wall from the short-circuit surface of the waveguide along the input side, and a metal bar post is inserted from one end of the microwave integrated circuit near the short-circuit surface of the waveguide to guide the wave. By combining the tube and the microwave integrated circuit, it is possible to achieve SH with less local signal radiation and good image blocking characteristics.
The present invention provides a microwave frequency converter having a very compact configuration using an F converter or the like.

DESCRIPTION OF EMBODIMENTS FIGS. 2a and 2b show a microwave frequency converter according to a first embodiment of the present invention. In Figures 2a and 2b, 22 is a rectangular waveguide with a local signal cut-off region and (7, RF double signal pass region) whose cross-sectional dimension is a″#14.
, b dust 7. 23 is a metal post inserted near the short-circuit surface of the waveguide 22 from the microwave integrated circuit 3;
2 and a microwave integrated circuit 3. Reference numeral 24 denotes a cylindrical Teflon rod, which is inserted into the insertion hole 26 of the metal post drilled in the waveguide 22, insulating the metal post 23 and the waveguide 22 with direct current, and partially connecting the coaxial line. The impedance is approximately 60Ω. 26
is a circular hole formed concentrically with the metal post 23 drilled in the ground conductor surface of the metal post insertion part of the input section of the microwave integrated circuit, and its diameter is set to the diameter of the waveguide hole for inserting the Teflon rod in 25 above. The width is smaller than the diameter of the microstrip line, and slightly larger than the width of the center conductor 4 of the microstrip line of the microwave integrated circuit 3. 29. 30 is an RF amplifier circuit provided in the microwave integrated circuit, 31 is a mixer circuit, 32 is a local oscillation circuit,
33 is a dielectric resonator for stabilizing oscillation, and 28 is a local oscillation frequency adjustment screw provided on the microwave integrated circuit shield case 27.

According to the first embodiment of FIGS. 2a and 2b configured as described above, the input RF signal from the waveguide 22 is transmitted to the metal post 2.
3. The configuration in which the diameter of the disk hole 26 provided on the ground conductor is smaller than the diameter of the waveguide hole 25 reduces loss due to line conversion in a wide band (for example, 11.7 GHz to 12.7 GHz). Input terminal 4 of microwave integrated circuit 3
supplied to

This human-powered RF multiplied signal is amplified by a two-stage RF amplifier circuit of 29.30 kHz, frequency-converted by a mixer circuit of 31 and a local oscillation circuit of 32 (oscillation frequency: 10.7 GHz), and an IF multiplied signal is extracted.

In such a configuration, even if the local oscillation signal is on the input side of the microwave integrated circuit, the waveguide 22 is cut-off for the local signal, so the radiation from the waveguide is attenuated within the waveguide. is sufficiently suppressed. In addition, since the microwave integrated circuit 3 is arranged on the input side of the waveguide 3 rather than on the short-circuited side, it is possible to make the microwave integrated circuit 3 longer by the length of the microwave integrated circuit 3 without increasing the overall size, thereby reducing local signal leakage. Sufficient attenuation within the waveguide 22 can be achieved with a simple and compact configuration.

FIG. 2C shows an example of the configuration of the microwave integrated circuit 3. In the same figure, the signal from the metal post 23 is amplified by RF amplification stages 29 and 3o made of microwave semiconductors such as GaA gFETs, and is supplied to the mixer circuit 31 via the image rejection filter 34, and is then passed through the dielectric resonator 33. The mixed signal is mixed with a local oscillation signal from the local oscillator 32 stabilized by the IF output 44, and is output as an IF output 44. Here, 35 and 3
7 is the gate bias resistor and high frequency choke circuit of the first stage and next stage amplifier, 36, 38, 39 is the drain resistor and high frequency choke circuit of the first stage and next stage amplifier and oscillation circuit 32, and 40.41 is each GaAs F
The ET oscillator 32 has a source resistance, a high frequency choke circuit, and a gate termination resistance, and 42 and 43 are DC blocking circuits. In this way, the RF amplifier circuit, mixer circuit,
By arranging the local circuits almost in series and compactly configuring them on a rectangular board, it is easy to integrate them with the waveguide, and the power supply terminals such as gates and drains can be connected in one direction, making production easier. I'm also good at sex.

FIG. 3 is a sectional view from the side and a sectional view from the waveguide input side of a microwave frequency conversion device showing a second embodiment of the present invention.

In the figure, the same numbers as in Figure 2 indicate the same items, and
The difference from the configuration shown in the figure is that a circular waveguide 46 is used instead of the rectangular waveguide 22, and its diameter C is selected to be approximately 16 mm to provide a cutoff region for the local oscillation frequency of 10.7 GH2.
It is selected so that it passes the RF multiplied signal in the 2 GHz band, thereby suppressing local signal radiation as in the first embodiment shown in FIG.

In addition to providing excellent performance in image disturbance characteristics, the waveguide 45 is circular, making it easier to manufacture in terms of quantity compared to a rectangular waveguide, and it is also suitable for antennas that support circularly polarized satellite broadcasting.
There are many secondary radiators of circular waveguide output type, and they have good matching with such circular output antennas. Third
In the figure, 46 is the shorting plate of the circular waveguide 45, and the distance from the shorting plate surface to the metal rod post 23 is Z and % of the tube wavelength λ.
The distance between the circular waveguide 46 and the microwave integrated circuit 3 is improved, and 47.48 is the distance between the shield case 27
A partition plate installed in the RF amplifier circuit is used to isolate and shield between the RF amplification circuits and between the RFF width circuit 30 and the mixer circuit 31, thereby minimizing the coupling between each circuit and reducing the local oscillation signal from the local oscillation circuit 32. It is designed to suppress the return to the RF stage. Further, 49 is a screw for fixing the shorting plate 46, and 6o is a matching screw provided near the center of the shorting plate 46 to adjust the input impedance.
This absorbs fluctuations in input impedance from the perspective of the input impedance. Reference numeral 51 denotes an intermediate frequency amplification circuit (IFF width circuit) installed on the external side of the waveguide 45 almost perpendicular to the microwave integrated circuit 3, and connects the IFF power terminal 44 of the microwave integrated circuit and the short coaxial line 62 to the waveguide. They are connected at the shortest distance through the through hole 63 of the chassis, which allows for a connection with less loss, and allows for a very compact and compact configuration as a microwave frequency converter.

FIG. 4 shows a sectional view from the side of a microwave frequency conversion device showing a third embodiment of the present invention and an input sectional view seen from the waveguide input side. In this figure, the same numbers as in FIG. 3 indicate the same parts, and the difference from FIG.
This makes it possible to use a rectangular waveguide as the waveguide input. The circular-rectangular waveguide conversion circuit 64 has a square rectangular waveguide 55 (a1 #15mm, b1 dust 18mm,
a1=12mm) and a long elliptical waveguide 66 (arc radius RL
;10m+n.

b Dust 13■, d2□□□8 throat) and rectangular waveguide 57 (W
B2 75, a #19.05mm, b3L; s, e
s ran ) connected in cascade, and by connecting this to the input of the circular waveguide 46 in Figure 3 as shown in Figure 4, the circular waveguide (CR62) and the rectangular waveguide It is possible to perform wide-band waveguide conversion with low insertion loss in the RFF band (e.g. 11.7 to 12.7 GHz) of the tube (WB76), and convert the circular waveguide input microwave frequency converter into a rectangular waveguide. The input can be easily converted without degrading performance such as noise figure. therefore,
If such a small circular-rectangular converter 54 is attached and integrated with the circular waveguide input microwave frequency converter shown in FIG. 3 as shown in FIG. 4, a circular waveguide that suppresses local signal radiation can be formed. It is possible to easily configure a rectangular waveguide input microwave frequency converter by taking advantage of the features of 46 and without degrading the original performance such as noise figure. In general, many microwave parabolic antennas and the like have a rectangular waveguide output, so the antenna can be used satisfactorily for such antennas.

Effects of the Invention The microwave frequency conversion device of the present invention uses a waveguide with a local signal cutoff region and an RF multiplied signal passband, and a microstrip line is fixed on the outer wall of the waveguide. By short-circuiting one end and performing waveguide-to-microstrip line conversion using a metal post near the short-circuit, and configuring the microstrip line from the short-circuited side of the waveguide to the input side, local signal radiation is reduced and the image is improved. It is possible to obtain a compact microwave frequency conversion device with a very simple structure and a good suppression characteristic, and its practical effects including mass production are very large.

View and circuit diagram of a microwave integrated circuit, FIG. 2a.

b, c are a cross-sectional side view, front view, and circuit diagram of the microwave frequency converter according to the first embodiment of the present invention; Fig. 3a,
b, Figures 4a and b are 2nd. FIG. 7 is a cross-sectional side view and a front view of a microwave frequency converter in a third embodiment.

3...Microwave integrated circuit, 22...
Rectangular waveguide circuit, 23...Metal post, 45.
...Circular waveguide, 46 ... Short circuit plate, 51
. . . IF amplification section, 64 . . . Circular-rectangular waveguide conversion section.

Name of agent: Patent attorney Toshio Nakao and 1 other person
1 figure

Claims (1)

[Claims] (1) One end of the waveguide, which has an RF multiplied signal pass band and a local signal with a lower frequency than the RF multiplied signal as a cutoff range, is short-circuited, and a microstrip line is installed on the outer wall of the waveguide. fixed,
A metal rod is inserted from one end of the five-wire center conductor of this microstrip line into the vicinity of the short-circuited surface of the conductive tube to couple the microstrip line and the waveguide, and the RF multiplied signal from the waveguide is A microwave frequency conversion device characterized in that frequency conversion is performed by a local oscillation circuit and a mixer circuit configured on the microstrip line. ? 2.) The microwave frequency conversion device according to claim 1, wherein the microstrip line is constructed from the short-circuit surface of the waveguide to the input aperture surface. (3) The microwave frequency conversion device according to claim 1 or 2, wherein the waveguide is a circular waveguide. (4) A chromatic wave frequency conversion device for the waveguide, in which the diameter of the insertion hole provided in the ground conductor of the microstrip line is adjusted in both the metal rod insertion holes through which the waveguide and the microstrip line are passed. (5) The microwave frequency according to claim 3, characterized in that a circular-rectangular waveguide device including an elongated waveguide and a square waveguide is provided on the input side of the circular waveguide. conversion device.