JP2004254223A - Waveguide input and output microwave circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide impedance matching, which abolishes two steps of transformation losses in the case of using a coaxial line and a transmission loss in a matching circuit and matching corresponding to individual difference of amplifiers. <P>SOLUTION: While an amplifier 24 is installed adjacent to a waveguide 20, a probes 25 is arranged in parallel to a electric field E of the waveguide 20. A movable screw 26 is provided for adjusting a distance D from the probe 25 to a shorting surface of the waveguide 20. Impedance matching of the waveguide 20 and the amplifier 24 can be attained by setting the length and the diameter of the probe 25 and adjusting the distance D with the movable screw 26. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
INDUSTRIAL APPLICABILITY The present invention is used as a waveguide input / output microwave circuit, particularly as a receiver and transmitter circuit of a communication device that transmits and receives microwaves and millimeter waves at a high frequency, from the waveguide section to the first or last stage amplifier. It relates to a circuit configuration.
[0002]
[Prior art]
FIG. 2 shows a first conventional example of a receiver (waveguide waveguide input / output microwave circuit) using a matching circuit. In the circuit of the first conventional example, as shown in FIG. 2, a metal frame 2 is arranged outside a main body 1, and a waveguide 3 is formed between the main body 1 and the metal frame 2. The upper surface of the waveguide 3 becomes the short surface 3S. On the upper side of the main body 1, a dielectric substrate 5 is formed over the metal frame 2, and a microstrip line 6 is formed on the dielectric substrate 5. A probe 7 protruding into the waveguide 3 is provided. An amplifier 8 is connected to the microstrip line 6, and a matching circuit 9 having a predetermined inductance and a capacitor is provided between the amplifier 8 and the probe 7.
[0003]
According to the configuration of the first example, the waveguide 3 and the microstrip line 6 are impedance-matched by setting the distance between the short surface 3S and the probe 7, and the impedance matching between the waveguide 3 and the amplifier 8 is performed. This is achieved by the matching circuit 9, whereby the conversion of the electromagnetic wave and the signal between the waveguide and the microstrip line and the signal amplification are performed well.
[0004]
FIG. 3 shows a second conventional example of a receiver that does not use a matching circuit. In the circuit of the second conventional example, as shown in FIG. 3, a dielectric substrate 12 is provided above a main body 11 in which a waveguide 10 is formed together with a short surface 10S. , A microstrip line 13 and an amplifier 14 are arranged. The dielectric substrate 12 and the microstrip line 13 are connected to the dielectric substrate 12 and the microstrip line 13, and a dielectric 15 and a probe 16 serving as a coaxial line are vertically arranged. The probe 16 protrudes into the waveguide 10.
[0005]
In the configuration of the second example, impedance matching between the microstrip line 13 and the coaxial line including the dielectric 15 and the probe 16 is achieved, and matching between the microstrip line 13 and the amplifier 14 is determined by the length of the protrusion of the probe 16. , Thickness, and the distance to the short surface 10S of the probe 16 are set to appropriate values.
[0006]
[Patent Document 1]
JP-A-5-136609
[Problems to be solved by the invention]
However, in the case of the waveguide input / output microwave circuit using the matching circuit 9 shown in the first conventional example, the received wave is attenuated due to the transmission loss caused by the matching circuit 9, so that the noise figure deteriorates. There was a problem.
Further, in the case of the second conventional example, since a coaxial line including the dielectric 15 and the probe 16 is used, the conversion between the waveguide 10 and the coaxial line and the conversion between the coaxial line and the microstrip line 13 are performed. , Two mode conversions are required. Therefore, there is a problem that conversion loss occurs in two stages and the performance of the amplifier 14 cannot be maximized.
[0008]
Furthermore, in this type of waveguide input / output microwave circuit, impedance mismatch may occur due to individual differences between the amplifiers 8 and 14 and variations in assembly. In the conventional example, there is a problem that such a mismatch cannot be easily adjusted.
[0009]
The present invention has been made in view of the above problems, and an object of the present invention is to eliminate the attenuation of a received wave due to a transmission loss of a matching circuit, and to eliminate a two-stage conversion loss when using a coaxial line. It is an object of the present invention to provide a waveguide input / output microwave circuit capable of maximizing amplifier performance and easily adjusting impedance matching with respect to individual differences between amplifiers and variations in assembly.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is directed to a waveguide input / output microwave circuit for forming a waveguide having a short surface in a main body and performing microwave input / output. An amplifier connected to the microstrip line at a position adjacent to the tube; a probe connected to the microstrip line and protruding into the waveguide in a direction parallel to the electric field of the waveguide; An adjusting mechanism for variably adjusting the distance from the probe to the short surface of the waveguide; setting the length and thickness of the probe and adjusting the adjusting mechanism to adjust the impedance between the waveguide and the amplifier; It is characterized by matching.
[0011]
According to the above configuration, as the adjusting mechanism, for example, a movable component such as a movable screw protruding from the reference short surface of the waveguide is disposed, and the impedance between the waveguide and the amplifier adjacent thereto is adjusted. The alignment is preferably performed by setting the length and thickness of the probe to optimal values and adjusting the amount of protrusion of the movable screw. According to the adjustment of the distance between the probe and the waveguide short surface by the movable screw, not only the impedance matching between the waveguide and the amplifier is performed, but also the mismatch due to individual differences of the amplifier itself and variations in assembly. It can be adjusted at the same time.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a configuration of a waveguide input / output microwave circuit used as a receiver according to an embodiment of the present invention. As shown in FIG. A metal frame 19 is disposed outside the base 18 (the main body 18 and the metal frame 19 are collectively referred to as a housing). A waveguide 20 is formed between the main body 18 and the metal frame 19, and a reference short surface 20S of the waveguide 20 is provided on the metal frame 19 side. A dielectric substrate 21 [which occupies the same area as the metal frame 19 in FIG. 1A] is formed over the metal frame 19 on the upper side of the main body 18. A microstrip line 22 is formed on a substrate 21. A probe 25 projecting into the waveguide 20 is provided connected to the microstrip line 22, and the probe 25 is arranged in parallel to the direction of the electric field E in the waveguide 20.
[0013]
In the embodiment, an amplifier 24 is connected to the microstrip line 22 at a position close to the probe 25 and adjacent to the waveguide 20, as shown in FIG. In addition, a movable screw (or other movable component) 26 that protrudes from the reference short surface 20S of the waveguide 20 to the inside and that can change the amount of protrusion is provided on the metal frame 19. The tip of the movable screw 26 serves as a short surface, and serves as an adjusting mechanism for adjusting the distance D (FIG. 1B) between the short surface and the probe 25. In this embodiment, this distance is set to λ / 4 or less (λ: Adjust within the range of the operating frequency).
[0014]
The length and thickness of the probe 25 protruding into the waveguide 20 are set to values that allow good impedance matching between the waveguide 20 and the amplifier 24 in consideration of the existence of the movable screw 26. In particular, the length of the probe 25 is set to a value of λ / 4 or less.
[0015]
The embodiment has the above configuration, and the received wave incident on the waveguide 20 is converted between the waveguide and the microwave strip line, and is guided to the input unit of the amplification unit 24 as a reception signal. The signal is amplified by the amplifier 24.
[0016]
In such an embodiment, the amplifier 24 is disposed adjacent to the waveguide 20, so that the transmission loss does not occur in the matching circuit as in the first conventional example, and the reception signal is attenuated. Can be suppressed. Further, unlike the second conventional example, two mode conversions such as conversion between a waveguide and a coaxial line and conversion between a coaxial line and a microstrip line are not performed. Therefore, the performance of the amplifier 24 can be maximized.
[0017]
Further, the length of the probe 25 is set to a value of λ / 4 or less, and the distance D between the probe 25 and the short surface is adjusted by the movable screw 26 in a short range of λ / 4 or less. The impedance on the waveguide 20 side can be matched so as to be minimized, and the mismatch due to individual differences of the amplifiers 24, variations in circuit assembly, and the like can be easily adjusted and corrected.
[0018]
In the above embodiment, the impedance matching on the waveguide 20 side was performed so that the noise figure of the amplifier 24 was minimized. However, the present invention is not limited to this, and the return loss (VSWR) of the amplifier 24 may be changed according to the type and function of the circuit. ), The power and the gain can be matched to the optimum impedance.
[0019]
Further, in the above embodiment, the circuit applied to the receiver has been described. However, the configuration in the case of the waveguide input / output microwave circuit used for the transmitter is also the same, and the same effect as above can be obtained.
[0020]
【The invention's effect】
As described above, according to the present invention, the amplifier is provided adjacent to the waveguide, and the distance from the probe arranged in a direction parallel to the waveguide electric field to the short surface of the waveguide is adjusted. The impedance is matched between the waveguide and the amplifier by setting the length and thickness of the probe and adjusting the adjustment mechanism, so that the reception due to the transmission loss of the matching circuit is achieved. Wave attenuation can be eliminated, and a two-stage conversion loss in the case of using a coaxial line can be eliminated to maximize the amplifier performance. In addition, it is possible to easily adjust impedance matching with respect to individual differences of amplifiers, variations in circuit assembly, and the like.
[0021]
In addition, by setting the length and thickness of the probe and appropriately adjusting the adjustment mechanism, the noise figure, the return loss, the power, the gain, and the like can be matched to the optimum impedance. Products can be easily manufactured. Furthermore, in comparison with the second conventional example, since the configuration is such that the coaxial / waveguide converter is eliminated, there is an advantage that circuit component costs and assembly costs can be reduced.
[Brief description of the drawings]
FIG. 1 shows a configuration of a waveguide input / output microwave circuit (receiver) according to an embodiment of the present invention. FIG. 1 (A) is a plan view and FIG. 1 (B) is a side sectional view.
2A and 2B show a configuration of a waveguide input / output microwave circuit (receiver) as a first conventional example, where FIG. 2A is a plan view and FIG. 2B is a side sectional view.
3A and 3B show a configuration of a waveguide input / output microwave circuit (receiver) as a second conventional example, where FIG. 3A is a plan view and FIG. 3B is a side sectional view.
[Explanation of symbols]
3, 10, 20 ... waveguide,
3S, 10S ... short side,
20S: Reference short surface,
6, 13, 22 ... microstrip line,
7, 16, 25 ... probe,
8, 14, 24 ... amplifier,
26: movable screw (adjustment mechanism).

Claims (1)

In a waveguide input / output microwave circuit that forms a waveguide having a short surface in the main body and performs input / output of microwaves,
An amplifier connected to the microstrip line at a position adjacent to the waveguide;
A probe connected to the microstrip line and protruding into the waveguide in a direction parallel to the electric field of the waveguide;
An adjustment mechanism for variably adjusting the distance from the probe to the short surface of the waveguide is provided,
A waveguide input / output microwave circuit, wherein impedance setting between the waveguide and the amplifier is achieved by setting the length and thickness of the probe and adjusting the adjustment mechanism.

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