JPS6231521B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor high-frequency circuit device in which, for example, a semiconductor element is mounted within a rectangular waveguide and a large amount of power passing through the rectangular waveguide is limited.

Conventionally, among high-frequency semiconductor devices, the development of high-power devices has been relatively slow, but in recent years, semiconductors have been significantly used in microwave radar devices. Conventional TR tubes for power limiting have also been replaced by semiconductor devices, and this semiconductorization has significantly improved the drawbacks of conventional TR tubes, such as short lifespan and slow response speed. However, new problems have arisen in this semiconductor process as well. This is because the impedance of this pin diode at low power varies widely due to variations in reactance, element resistance, capacitance, or case capacitance of the bonding wire of the PIN diode that replaced the TR tube. Simply attaching the waveguide between the upper and lower wide walls using rod screws does not provide satisfactory operation, and requires many man-hours of adjustment for each element.

An object of the present invention is to obtain a high frequency circuit device in which the above-mentioned variations in semiconductor elements can be extremely easily corrected.

Next, the present invention will be explained in detail using a microwave limiter using a pin diode as an example. That is, in FIGS. 1a and 1b, 1 is a rectangular waveguide as a microwave transmission path, and the upper wall 1a of the rectangular waveguide is located approximately at the center of the upper and lower wide walls 1a, 1a' in the width direction. , a metal screw 2 having a cylindrical cavity 2a is screwed in with the cylindrical cavity 2a directed into the waveguide. A stepped metal cylinder 3 having a thick base 3a and a thin tip 3b is screwed into the lower wall 1a' facing the metal screw, and the metal screw 2 is connected to the tip of the tip 3b.
A pin diode 4 is connected between the bottom surface of the cylindrical cavity 2a and the bottom surface of the cylindrical cavity 2a.
is installed.

Now, to describe the case where microwave power enters from the input port IN of this waveguide 1 and exits from the output port OUT, the electric field distribution inside the waveguide is as shown in FIG. and 1a', the distribution is zero at both ends in the width direction and maximum at the center position. When the microwave power applied to the diode 4 is low, the rectified power is small and the element impedance is high, and the power loss in the pin diode 4 can be ignored, and the incident power passes through the waveguide 1 and exits to the output port out. However, when the power is high, the element impedance rapidly decreases due to the rectifying action of the pin diode 4, and the waveguide 1 becomes short-circuited, and the incident power is reflected and the passage through the waveguide 1 is restricted.

By the way, in this high frequency circuit device, the cylindrical cavity 2
a constitutes a coaxial line together with the cylinder 3. This coaxial line is inserted into the rectangular waveguide 1 so that the outer conductor metal screw 2 of the coaxial line acts as an inductive impedance to cancel the capacitive impedance of the pin diode 4 when a low power microwave is input. At this time, the pin diode 4 is placed in parallel with the rectangular waveguide 1. Next, the cylindrical cavity 2a
When a high-power microwave is applied to the pin diode 4, a rectifying action occurs, causing a direct current to flow through the pin diode 4, rapidly decreasing the impedance and creating a short circuit. The inductive impedance of the bonding wire inside the case No. 4 remains. In order to cancel this inductive impedance, capacitive impedance is formed in the cylindrical cavity 2a. Here, the mechanical dimensions of the coaxial line are determined by the impedance of the pin diode, but some adjustment is required.
and the outer conductor metal screw 2 to move them together in the vertical direction within the waveguide, thereby making the correction. As mentioned above, there are variations in the impedance of the pin diode 4 in low-power microwaves, and a drop in the resistance component in particular results in power loss.In order to reduce this, the characteristic impedance of the part where the pin diode 4 is attached is changed. The decrease in the resistance component is corrected by lowering the resistance.

That is, conventionally, the inner conductor metal screw part is made of one kind of uniform thickness, but the circuit of the present invention is composed of a cylinder part 3b of a conventional thickness and a cylinder part 3a of a different thickness, so that it can be screwed through. It is in electrical contact with the rectangular waveguide 1. As this portion of the cylinder 3a is inserted into the rectangular waveguide 1, the characteristic impedance of the portion where the pin diode is attached decreases. On the contrary, when the cylinder 3a sinks into the a' wall of the rectangular waveguide 1, the characteristic impedance increases.

Moreover, the correction is made by moving the metal cylinder 3 and the outer conductor metal screw 2 integrally into the waveguide in the vertical direction, and the dimensions of the coaxial line are constant, so the alignment with the waveguide is corrected. Never collapses.

As an example of the present invention, a semiconductor limiter for a 9400 MHz band radar device was constructed. As a result, the variation in the low power impedance of pin diodes has expanded from being adjustable to a range of about 10% from the center value to a range of about 25%. The adjustment speed is also approximately 1.5 times faster than conventional circuits.

[Brief explanation of the drawing]

FIG. 1a is a sectional view of a semiconductor limiter using a rectangular waveguide. Figure b is a left side view of figure a. FIG. 2 is a diagram showing the electric field distribution within a rectangular waveguide. 1... Rectangular waveguide, 1a... Rectangular waveguide wide upper wall, 1a'... Rectangular waveguide wide lower wall, 2... Metal screw, 2a... Cylindrical cavity of metal screw 2, 3... Cylindrical column, 3a... Root portion of column 2, 3b... Tip portion of column 2, 4... Semiconductor element (pin diode).

Claims (1)

[Claims] 1. A rectangular waveguide, and a metal screw having a cylindrical cavity screwed into the waveguide with the cylindrical cavity facing the waveguide at a substantially central position in the width direction of one of the wide upper and lower walls of the rectangular waveguide; A stepped metal cylinder with a thin tip and a thick base is screwed into the other wide wall opposite the metal screw, and the metal screw is installed between the tip of the metal cylinder and the bottom of the cylindrical cavity of the metal screw. A semiconductor high-frequency circuit device comprising: a semiconductor element, the metal screw and the metal cylinder being integrally moved in the vertical direction within the waveguide to adjust the characteristic impedance of the semiconductor element portion. .