JPH10209899A - Low noise converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a crossing part between a horizontally polarized wave reception signal and a vertically polarized wave reception signal on a board. SOLUTION: Print patterns 51, 53 through which a vertically polarized wave reception signal is propagated are split and an earth pattern is formed inbetween. The separated print patterns 51, 53 are connected by a surface mount component 52. A print pattern 55 of a crossing part among print patterns 54, 55, 56 through which a horizontally polarized wave reception signal is propagated in crossing with the print patterns 51, 53 is formed to a rear side of a printed circuit board and the print patterns 54, 56 on the front side and the print pattern 55 formed on the rear side are connected by throughholes 54-1, 56-1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for receiving broadcast waves transmitted by vertical polarization and horizontal polarization, such as satellite broadcasting,
The present invention relates to a low-noise converter capable of arbitrarily selecting any broadcast wave reception output and outputting the output from two output units.

[0002]

2. Description of the Related Art BS broadcasting and CS broadcasting are currently performed in satellite broadcasting. Among them, BS broadcasting is broadcasted by circularly polarized radio waves, and CS broadcasting is broadcasted by linearly polarized waves. In CS broadcasting, transmission is performed using horizontally polarized waves and vertically polarized waves that are orthogonal to each other. For this reason, a low-noise converter (LNB) that receives CS broadcasts can distinguish between horizontally polarized waves and vertically polarized waves and receive them.

FIG. 4 shows an example of a conventional circuit block of this type of LNB for CS. In FIG. 4, a vertical polarization input (V IN) and a horizontal polarization input (H IN) usually consist of a conical horn and a circular waveguide arranged at the focal point of a radio wave focused by a parabolic reflector. These are a vertically polarized wave reception signal and a horizontally polarized wave reception signal received by the primary radiator and discriminated by the polarization division unit. The vertically polarized input is amplified by a high-frequency amplifier (RF Amp) 101,
X) 102 to convert to an intermediate frequency. The signal is amplified by an intermediate frequency amplifier (IF Amp) 103 and divided into two by a divider (DIV) 104. One of the divided outputs is supplied to a first V / H switching circuit 105, and the other is outputted to a second V / H switching circuit 105.
Is supplied to the V / H switching circuit 115.

A horizontally polarized input is connected to a high-frequency amplifier (RF
The signal is amplified by an amplifier (Amp) 111 and converted to an intermediate frequency by a mixer (MIX) 112. Then, the signal is amplified by an intermediate frequency amplifier (IF Amp) 113 and is distributed to a distributor (DIV) 11.
4 and one of the divided outputs is the first V / H
The other distributed output is supplied to the switching circuit 105 and the second V / H switching circuit 115. Note that the local oscillation output generated by the local oscillator (Lo) 122 is supplied to the mixer 102 and the mixer 112, and the frequency of the received signal is converted into an intermediate frequency signal.

The first V / H switching circuit 105 includes a horizontal selection switch 105-1 and a vertical selection switch 105-2, and when one of the switches is turned on,
The first switch control circuit (CONT) 109 controls the remaining switches to be turned off. Also, the second V / H
The switching circuit 115 includes a horizontal selection switch 115-2 and a vertical selection switch 115-1.
The second switch control circuit (CONT) 119 controls so that one switch is turned on and the remaining switches are turned off. Here, as shown in FIG. 4, when the vertical selection switch 105-2 of the first V / H switching circuit 105 is turned on and the horizontal selection switch 105-1 is turned off, the first V / H switching is performed. The vertical polarization input converted to the intermediate frequency selected by the circuit 105 is output via the mixer 106. The intermediate frequency signal output from the mixer 106 is amplified by an intermediate frequency amplifier (IF Amp) 107 and output from a first output terminal OUT1.

When the horizontal selection switch 115-2 of the second V / H switching circuit 115 is turned on and the vertical selection switch 115-1 is turned off, as shown in FIG.
The horizontal polarization input converted to the intermediate frequency selected by the second V / H switching circuit 115 is output via the mixer 116. The intermediate frequency signal output from the mixer 116 is amplified by an intermediate frequency amplifier (IF Amp) 117 and output from a second output terminal OUT2.

Next, the operation of the first switching control circuit 109 and the second switching control circuit 119 will be described. The first switching control circuit 109 and the second switching control circuit 119 perform the operation of the input DC voltage. Switching control is performed to select either a vertically polarized signal or a horizontally polarized signal depending on the magnitude.
The DC voltage at this time is input from the first output terminal OUT1 and the second output terminal OUT2. This DC voltage is a power supply for operating the LNB, and the LNB output arranged near the TV receiver is used as the DC voltage. It is supplied to the LNB from the supplied CS tuner via a coaxial cable. Therefore, the DC voltage input from the first output terminal OUT1 is supplied to the switching control circuit 10 via the choke coil 108.
9 and a backflow prevention diode 11
0 to the common power supply circuit 121. The DC voltage input from the second output terminal OUT2 is supplied to the switching control circuit 119 via the choke coil 118.
And a backflow prevention diode 120
Is supplied to the common power supply circuit 121 via the. Power is supplied from the common power supply circuit 121 to each part of the LNB.

When the magnitude of the DC voltage input from the first output terminal OUT1 is the first voltage value, the vertical selection switch 105-2 is turned on and the horizontal selection switch 105-1 is turned off. The first switching control circuit 109 controls the first V / H switching circuit 105 so that
When the magnitude of the DC voltage input from the first output terminal OUT1 is the second voltage value, the vertical selection switch 105-2 is turned off, and the horizontal selection switch 105-1 is turned off.
Is switched on, the first switching control circuit 109 controls the first V / H switching circuit 105. Further, the magnitude of the DC voltage input from the second output terminal OUT2 is the first voltage.
, The vertical selection switch 115-
1 is turned on and the horizontal selection switch 115-2 is turned off, the second switching control circuit 119 controls the second V / H switching circuit 115, and the DC input from the second output terminal OUT2. When the magnitude of the voltage is the second voltage value, the second switching control circuit 119 sets the second V so that the vertical selection switch 115-1 is turned off and the horizontal selection switch 115-2 is turned on. / H switching circuit 115 is controlled.

Thus, it is possible to output a reception output of an arbitrary polarization independently from the first output terminal OUT1 and the second output terminal OUT2. Note that the backflow prevention diode 110 is connected to the second output terminal OUT.
The first switching control circuit 1 is controlled by the DC voltage input from
09 prevents malfunction, and the backflow prevention diode 120 prevents the second switching control circuit 119 from malfunctioning due to the DC voltage input from the first output terminal OUT1.

[0010]

The LNB having the above-described configuration
In the circuit of FIG. 1, the first V / H
A conductive path that guides the horizontally polarized wave reception signal to the switching circuit 105 and a conductive path that guides the vertically polarized wave reception signal to the second V / H switching circuit 115 intersect at an intersection point. The signal crossing at this crossing point is an intermediate frequency signal,
Since the signal is a high-frequency signal of 2 Hz to 2 GHz, it is necessary to consider that the vertically polarized wave reception signal and the horizontally polarized wave reception signal do not interfere with each other at the intersection point and that there is no loss at the intersection point. Here, if the isolation between the vertically polarized wave reception signal and the horizontally polarized wave reception signal deteriorates at the intersection point, the mutual reception signals interfere with each other, and a reception failure occurs.

Therefore, in order to prevent a reception failure from occurring, conventionally, as shown in FIGS.
It is separated into two substrates, an F substrate and an IF substrate. The RF substrate shown in FIG.
1, mixer 102, IF Amp103 and its output terminal V-IF
OUT, an RF Amp 111, a mixer 112, an IF Amp 113 in a horizontal polarization receiving section, and an output terminal H-IF OUT thereof. Further, a local oscillator (Lo) 122 that supplies a local oscillation output to the mixers 102 and 112 is provided. The IF board shown in FIG. 6 includes a vertical polarization signal input terminal V-IF IN, distributor 104, a horizontal polarization signal input terminal H-IF IN, distributor 114, and a horizontal selection switch 1.
05-1 and a vertical selection switch 105-2.
V / H switching circuit 105 and horizontal selection switch 115-
2 and a second V /
H switching circuit 115 and first output terminal mixer 10
6, IF Amp 107, its output terminal OUT1,
, An output terminal system mixer 116, IFAmp 117, and an output terminal OUT2.

[0012] Then, the RF substrate and the IF substrate thus separated into two are overlapped, and the vertically polarized output terminal of the RF substrate is placed.
Connect the V-IF OUT and H-IF OUT
An LNB circuit is configured by connecting the vertical polarization signal input terminal V-IF IN and the horizontal polarization signal input terminal H-IF IN of the board with a lead wire or the like. As a result, desired isolation between the vertically polarized signal and the horizontally polarized signal can be achieved, and the occurrence of reception failure can be prevented.

However, in this method, since the LNB circuit is provided separately on the two substrates, there is a problem that the number of assembly steps increases. In addition, there is a problem that the cost increases because the number of assembling steps increases. The present invention has been made to solve such a problem, and an object of the present invention is to provide a low-noise converter that can reduce the number of assembly steps and the manufacturing cost.

[0014]

To achieve the above object, a low noise converter according to the present invention comprises a vertical polarization receiving circuit, a horizontal polarization receiving circuit, and an output from the vertical polarization receiving circuit. A first output unit and a second output unit for independently outputting any one of the outputs from the horizontal polarization receiving circuit, and the first output unit and the second output unit,
A first selection unit or a second selection unit for selecting one of an output from the vertical polarization receiving circuit and an output from the horizontal polarization receiving circuit;
At the intersection of the conductive paths for guiding the output from the vertical polarization receiving circuit and the output from the horizontal polarization receiving circuit to the selecting means and the second selecting means, one conductive path is provided on the back surface of the printed circuit board. A part of the formed conductive path is used, and the other conductive path uses a conductive path formed on the surface of the printed circuit board.

Further, at the intersection of the conductive paths of the low noise converter, the other conductive path is divided at the intersection, and the two divided conductive paths are connected by a surface mount component. And at the same time the divided 2
An earth pattern is formed between the conductive paths of the book.

According to the present invention, since the low-noise converter can be constituted by one substrate, the number of assembling steps can be reduced and the manufacturing cost can be reduced. Further, by dividing the other conductive path at the intersection point and forming an earth pattern between the two divided conductive paths, a sufficient isolator between the vertical polarization signal and the horizontal polarization signal is obtained even at the intersection point. Rations can be obtained.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view showing the structure of a primary radiator having a low-noise converter according to an embodiment of the present invention.
The primary radiator and the parabolic reflector constitute a satellite broadcast receiving antenna. In FIG. 1, 1
Is a circular waveguide into which orthogonal polarization consisting of vertical polarization and horizontal polarization is input, 2 is a conical horn attached to the tip of the circular waveguide 1, and 3 is the end of the circular waveguide 1. A vertical polarization short-circuiting surface, and a distance between the vertical polarization short-circuiting surface 3 and a later-described vertical polarization receiving probe 12 formed on the printed circuit board 7 is approximately λg / 4 (where λg is a guide wavelength). ing.

Reference numeral 4 denotes a slit elongated in the tube axis direction of the circular waveguide 1 connecting the circular waveguide 1 and the rectangular waveguide 5, and 5 denotes a circular guide in the tube axis direction. The rectangular waveguide 6 is a direction perpendicular to the tube axis direction of the waveguide 1 and is formed integrally with the circular waveguide 1. And the distance between the horizontal polarization short-circuit surface 6 and a later-described horizontal polarization receiving probe 32 formed on the printed circuit board 7 is approximately λg / 4 (λg
Is the guide wavelength). Reference numeral 7 denotes a printed circuit board which cuts the circular waveguide 1 and the rectangular waveguide 5 halfway and is inserted and arranged therebetween. The printed circuit board 7 has a circuit of the low noise converter of the present invention as shown in FIG. Is incorporated.

In the primary radiator configured as described above, when the orthogonal polarization consisting of the horizontal polarization and the vertical polarization is input to the circular waveguide 1 via the conical horn 2, the orthogonal polarization becomes circular. The light propagates through the waveguide 1. In this case, since the vertical polarization receiving probe 12 formed on the printed circuit board 7 stands vertically in the circular waveguide 1, the electric field direction of the vertical polarization component and the vertical polarization receiving probe 12 The extension direction matches, and the vertically polarized wave component is received by the vertically polarized wave receiving probe 12. On the other hand, the horizontal polarization component is not received by the vertical polarization receiving probe 12 because the direction of the electric field is orthogonal to the vertical polarization receiving probe 12, Through the slit 4 which is provided in a long and narrow manner. Then, the light propagates into the rectangular waveguide 5 connected to the circular waveguide 1.
Since the extending direction of the horizontal polarization receiving probe 32 erected on the rectangular waveguide 7 so as to be orthogonal to the vertical polarization receiving probe 12 matches the electric field direction of the horizontal polarization component, The horizontal polarization component is received by the polarization reception probe 32.

Since the direction of the electric field of the vertical polarization component coincides with the major axis direction of the slit 4, the vertical polarization component cannot pass through the slit 4 and is reflected by the slit 4. Only propagated. The length of the slit 4 in the tube axis direction is approximately λg / 2. Here, λg is a guide wavelength. As described above, since only the horizontally polarized wave component can be guided to the rectangular waveguide 5, the cross polarization of the signals received by the vertically polarized wave receiving probe 12 and the horizontally polarized wave receiving probe 32 is obtained. It is possible to provide a polarization splitting means having excellent discrimination.

The distance between the short-circuit surface 8 that terminates the circular waveguide 1 and the vertically polarized wave receiving probe 12 is determined by setting the guide wavelength to λ.
g, approximately λg / 4, the short-circuit surface 8 allows the phase of the vertically polarized wave in the circular waveguide 1 to be matched, and the peak of the electric field component of the vertically polarized wave becomes vertically polarized. This is the position of the wave receiving probe 12. Therefore, a sufficient vertical polarization receiving electric field can be obtained. Further, the distance between the short-circuiting surface 9 terminating the rectangular waveguide 7 and the horizontally polarized wave receiving probe 32 is also approximately λg / 4. Therefore, the phase of the horizontal polarization in the rectangular waveguide 7 is adjusted by the short-circuit surface 9, and the peak of the electric field component of the horizontal polarization is at the position of the horizontal polarization receiving probe 32. Thereby, a sufficient horizontal polarization receiving electric field can be obtained.

A notch 31-1 is formed in the printed circuit board 7 as shown in FIG. This notch 31-1
Is formed by cutting out the printed circuit board 7 located in the rectangular waveguide 5 from the slit 4 to the horizontal polarization receiving probe 32. Therefore, it passes through the slit 4, propagates in the rectangular waveguide 5, and receives the horizontally polarized wave reception probe 32.
Since the horizontally polarized wave component received at (1) propagates in the air until it is received, it can be received without receiving the propagation loss due to the printed circuit board 7. This allows
It is possible to prevent the NF characteristic of the received signal of the horizontal polarization component from deteriorating.

Next, the circuit configuration of the circuit board shown in FIG. 3 in which the circuit of the low noise converter according to the embodiment of the present invention is incorporated will be described. In FIG. 3, reference numeral 1 denotes a printed circuit board on which all the low noise converter circuits are assembled.
As described above, the radio wave focused by the parabolic reflector is converted into a circular waveguide portion disposed in the circular waveguide 1 of the primary radiator including the conical horn 2 and the circular waveguide 1 disposed at the focal point. 11 and a rectangular waveguide portion 31 arranged in the rectangular waveguide 5 through which the horizontally polarized reception signal split by the polarization splitting portion is propagated, is formed on the printed circuit board 7 by the printed pattern 8. I have. The notch 31-1 formed in the rectangular waveguide portion 31 of the printed circuit board 7 is formed by an epoxy glass material or Teflon, which is a base material of the printed circuit board 7. Notch to prevent attenuation by material.

Probe 1 located in circular waveguide section 11
2 is amplified by a high frequency amplifier (RF AMP) 13 and converted into an intermediate frequency by a mixer 14. Then, the signal is amplified by the intermediate frequency amplifier 15 and divided into two by the distributor 16. One of the divided outputs is supplied to the first V / H switching circuit 17, and the other is outputted to the second V / H switching circuit 37. Supplied. The horizontally polarized wave reception signal output from the probe 32 located in the rectangular waveguide section 31 is amplified by the high frequency amplifier 33 and converted to an intermediate frequency by the mixer 34. Then, the signal is amplified by the intermediate frequency amplifier 35 and is divided into two by the distributor 36. One of the divided outputs is supplied to the first V / H switching circuit 17.
The other distributed output is supplied to a second V / H switching circuit 37.

The high-frequency amplifier 13 and the high-frequency amplifier 3
3 is supplied with power for operation from an RF AMP power supply circuit 45, and a local oscillation output generated by a local oscillator 46 is supplied to the mixers 14 and 34, and the received signal is converted into an intermediate frequency signal. Frequency conversion. Further, the printed circuit board 7 is provided for the mixers 14 and 34.
A filter circuit for blocking the passage of unnecessary waves formed by the printed pattern is built therein.

The first V / H switching circuit 17 has a vertical selection switch 17-1 and a horizontal selection switch 17-2, so that one of them is turned on and the other switch is turned off. It is controlled by the first switching control circuit 22. Further, the second V / H switching circuit 37 includes a horizontal selection switch 37-1 and a vertical selection switch 37-2, and one of the switches is turned on and the other switch is turned off. 2 is controlled by the switching control circuit 42. Here, as shown in FIG. 2, when the vertical selection switch 17-1 of the first V / H switching circuit 17 is turned on and the horizontal selection switch 17-2 is turned off, the first V / H switching is performed. The vertical polarization input converted to the intermediate frequency selected by the circuit 17 is output via the mixer 18. The intermediate frequency signal output from the mixer 18 is amplified by the intermediate frequency amplifier 19 and output from the first output terminal OUT1.

When the horizontal selection switch 37-1 of the second V / H switching circuit 37 is turned on and the vertical selection switch 37-2 is turned off, as shown in FIG.
The horizontal polarization input converted to the intermediate frequency selected by the / H switching circuit 37 is output via the mixer 38. The intermediate frequency signal output from the mixer 38 is amplified by the intermediate frequency amplifier 38 and output from the second output terminal OUT2.

Next, the operation of the first switching control circuit 22 and the second switching control circuit 42 will be described. The first switching control circuit 22 and the second switching control circuit 42 The first V / H switching circuit 17 selects either a vertically polarized signal or a horizontally polarized signal depending on the magnitude.
And the second V / H switching circuit 37 is switched.
The DC voltage at this time is input from the first output terminal OUT1 and the second output terminal OUT2, and this DC voltage is a power supply for operating the low noise converter, and is a low power source arranged near the TV receiver. The noise converter output is supplied from the CS tuner to the low noise converter via a coaxial cable. For this reason, the DC voltage input from the first output terminal OUT1 is supplied to the switching control circuit 22 via the choke coil 20 formed by the printed pattern, and furthermore, the common power supply circuit via the backflow prevention diode 21. 48. The DC voltage input from the second output terminal OUT2 is supplied to the switching control circuit 42 via the choke coil 40 in a printed pattern, and further supplied to the common power supply circuit 48 via the backflow prevention diode 41. ing. Power is supplied from the common power supply circuit 48 to each part of the low noise converter.

When the magnitude of the DC voltage input from the first output terminal OUT1 is the first voltage value, the vertical selection switch 17-1 is turned on and the horizontal selection switch 17-2 is turned off. The first switching control circuit 22 controls the first V / H switching circuit 17 so that the magnitude of the DC voltage input from the first output terminal OUT1 is equal to the second voltage.
, The vertical selection switch 17-1
Is turned off, and the first switching control circuit 22 controls the first V / H switching circuit 17 so that the horizontal selection switch 17-2 is turned on. Further, when the magnitude of the DC voltage input from the second output terminal OUT2 is the first voltage value, the vertical selection switch 37-2 is turned on and the horizontal selection switch 37-1 is turned off. The second switching control circuit 42 controls the second V / H switching circuit 37, and when the magnitude of the DC voltage input from the second output terminal OUT2 is the second voltage value, the vertical selection is performed. Switch 3
The second switching control circuit 42 controls the second V / H switching circuit 37 so that 7-2 is turned off and the horizontal selection switch 37-1 is turned on.

By supplying a predetermined DC voltage from the CS tuner to the first output terminal OUT1 and the second output terminal OUT2 of the low noise converter, the first output terminal OUT1 and the second output terminal OUT2 are provided. Thus, it is possible to output the reception output of an arbitrary polarization independently from each other. The backflow prevention diode 21
Prevents the first switching control circuit 22 from malfunctioning due to the DC voltage input from the second output terminal OUT2, and the backflow prevention diode 41 is connected to the first output terminal OUT2.
A second switching control circuit 4 based on the DC voltage input from
2 prevents malfunction. Further, the choke coil 20 and the choke coil 40 prevent the high-frequency signal from leaking to the paths of the first switching control circuit 22 and the second switching control circuit 42.

Next, the configuration of the intersection point 47 surrounded by a broken line in FIG. 2, which is a feature of the low noise converter of the present invention, will be described in detail with reference to an enlarged detailed diagram shown in FIG. FIG. 3 shows a print pattern formed on the surface of the printed circuit board 7. The print pattern 51 and the print pattern 53 constitute a vertically polarized signal propagation line, and are separated at the center. The print pattern 54, the print pattern 55, and the print pattern 56 constitute a horizontal polarization signal propagation line.
Is formed on the back surface. And print pattern 5
An earth pattern is formed on the surface of the printed circuit board 7 excluding 1, 53, 54 and 56. Therefore, an earth pattern is formed between the print pattern 51 and the print pattern 53.

Further, the divided print pattern 51
The printed pattern 53 is connected to the printed pattern 53 by a surface mounted component 52 such as a capacitor mounted on the printed circuit board 7. The printed pattern 54 and the printed circuit board 7
Is connected to the printed pattern 55 formed on the back surface of the printed pattern 5 through a through hole 54-1.
5 and the printed pattern 56 formed on the surface of the printed circuit board 7 are connected by through holes 56-1. Furthermore, the ground pattern formed on the front surface of the printed circuit board 7 and the ground pattern formed on the back surface of the printed circuit board 7 are connected by a large number of through holes 60 at intersection points 47. As described above, at the intersection point 47, the horizontal polarization signal line and the vertical polarization signal line intersect via the ground pattern, so that a sufficient value of isolation between the two lines is obtained. Will be able to do it.

The surface mount component 52 is not limited to a capacitor, and any component may be used as long as it has a low impedance to a high frequency signal. In addition, the above-described novel configuration in which the horizontal polarization reception signal line and the vertical polarization reception signal line intersect on one substrate is not limited to the low noise converter, and can arbitrarily change the vertical polarization and the horizontal polarization. The present invention can also be applied to a polarization plane switch that can be switched. Furthermore, the printed circuit board 7 is shown as being exposed in FIG. 1, but is actually covered and shielded by a waterproof metal case. In addition, a coaxial connector is provided at an end of the metal case for extracting signals from the first output terminal OUT1 and the second output terminal OUT2. Further, as the substrate material of the printed circuit board 7, a glass epoxy base material, a Teflon base material, or the like can be used.

[0034]

As described above, according to the present invention, a low-noise converter circuit including an intersection point can be formed on a single printed circuit board to reduce the size. For this reason, the assembly process of the low noise converter can be reduced, and the manufacturing cost can be reduced. Further, the other conductive path is divided at the intersection point,
Since the ground pattern is formed between the conductive paths, sufficient isolation can be obtained between the vertically polarized reception signal and the horizontally polarized reception signal.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a primary radiator including a printed circuit board in which a circuit of a low-noise converter according to an embodiment of the present invention is incorporated.

FIG. 2 is a diagram illustrating a configuration of a printed circuit board in which a circuit of the low noise converter according to the embodiment of the present invention is incorporated.

FIG. 3 is a diagram showing a configuration of an intersection point in the circuit of the low noise converter of the present invention.

FIG. 4 is a circuit block diagram of a conventional low noise converter.

FIG. 5 is a diagram showing a configuration of an RF board of a conventional low noise converter.

FIG. 6 is a diagram showing a configuration of an IF board of a conventional low noise converter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Circular waveguide 2 Conical horn 3 Vertical polarization short-circuit plane 4 Slit 5 Rectangular waveguide 6 Horizontal polarization short-circuit plane 7 Printed circuit board 8 Print pattern 11 Circular waveguide section 12, 32 Probe 13, 33 High frequency amplifier 14, 34 mixer 15, 19, 35, 39 intermediate frequency amplifier 16, 36 distributor 17, 37 V / H switching circuit 18, 38 mixer 20, 40 choke coil 21, 41 backflow prevention diode 22, 42 switching control circuit 31 rectangular waveguide Tube 31-1 Notch 45 RF AMP power supply circuit 46 Local oscillator 47 Intersection point 48 Common power supply circuit 51, 53, 54, 55, 56 Print pattern 52 Surface mount component 54-1, 56-1, 60 Through hole

Claims (2)

[Claims] 1. A vertical polarization receiving circuit, a horizontal polarization receiving circuit, an output from the vertical polarization receiving circuit, and an output from the horizontal polarization receiving circuit, respectively. A first output section and a second output section, wherein the first output section and the second output section each include an output from the vertical polarization receiving circuit, and an output from the horizontal polarization receiving circuit. A first selector or a second selector for selecting one of an output and an output from the vertical polarization receiving circuit, the first selector and the second selector, and the first selector and the second selector. At the intersection of the conductive paths leading to the output from the polarization receiving circuit, one conductive path uses a part of the conductive path formed on the back surface of the printed circuit board, and the other conductive path uses the front surface of the printed circuit board. Characterized by utilizing conductive paths formed in Noise converter. 2. At the intersection of the conductive paths, the other conductive path is divided at the intersection, and the two divided conductive paths are connected by a surface mount component, and 2. The low noise converter according to claim 1, wherein an earth pattern is formed between the two conductive paths.