JPS6230528B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a microwave semiconductor device configured using a microstrip line and a slot line and operating as a miniaturized mixer or phase modulator.

Before describing the details of this invention, a conventional device of this type will be explained first.

Figure 1 is a diagram showing a conventional mixer. In the figure, the part indicated by the solid line is the slot line constructed on the ground conductor surface of the microwave integrated circuit board, and the part indicated by the broken line is the slot line constructed on the back surface of the board. The strip conductor of the microstrip line is shown.

The operation of a conventional mixer will be explained according to the diagram.

Signal power is provided by signal microstrip line 1.
The signal propagates through the slot line 2 and is applied in phase to the mixer diodes 4 and 5 placed at the branch 3 of the slot line. The local oscillation power passes through a local oscillation microstrip line 6, a capacitor 7, a microstrip line 8, and is distributed to slot lines 10 and 11 by a branch 9 between the microstrip line and the slot line. and is added to mixer diodes 4 and 5 in opposite phase. Since the IF output is generated between the ground conductor 12 and the ground conductor 13 surrounded by the slot lines 10 and 11, it is obtained from the microstrip line 8 through the low-pass filter 14. In the conventional mixer that operates as a mixer as described above, the signal power is coupled from the signal microstrip line 1 to the slot line 2 at the intersection 15, but the electromagnetic field at the intersection 15 is Because of the disturbance, if the length of the slot line 2 is short, the signal power is not evenly distributed to the mixer diodes 4 and 5 placed at the branch part 3 of the slot line, which adversely affects the characteristics of the mixer. For this purpose, the length of the slot line 2 is generally set to about 1/4 wavelength, and the signal power is distributed to the mixer diodes after the electromagnetic field of the slot line 2 is stabilized. However, when microwave power propagates through a slot line, the current is concentrated at the edges of the thin metal film, so the loss per unit length is greater than in a microstrip line. Therefore, in the conventional mixer shown in Figure 1, the signal line is
Since a slot line with a length of about four wavelengths is required, the loss of the signal line increases and the conversion loss becomes large.

Furthermore, since the length of the slot line 2 is required to be about 1/4 wavelength, there is a drawback that it is difficult to miniaturize the slot line 2.

Furthermore, in the conventional mixer, the branch 9 between the microstrip line and the slot line requires a conduction hole 16 to connect the front and back sides of the board in order to couple the IF power to the microstrip line 8. . For this reason, conventional mixers using substrates made of alumina, quartz, etc. have the drawback of not only deteriorating the characteristics of the mixer but also prolonging the machining time due to poor drilling accuracy.

In order to eliminate these drawbacks, this invention
A diode is connected to the space between the slot lines of the book, a signal microstrip line is placed behind it, and a thin strip line is connected to the ground conductor surrounded by the slot lines. The drawings will be explained in detail below.

FIG. 2 is a diagram showing an embodiment of the invention.

A case in which the microwave semiconductor device according to the present invention shown in FIG. 2 is operated as a mixer will be described with reference to the drawings.

Slot lines 10, 1 are arranged on the ground conductor of the signal microstrip line 1 with narrower spacing than before.
1, the signal microstrip line and the slot lines 10, 11 intersect at the intersection 15, and mixer diodes are connected to the slot lines 10, 11 at the intersection, respectively. Therefore, the current due to the signal power flowing in the ground conductor of the signal microstrip line 1 flows through the slot line 1.
However, since the mixer diodes 4 and 5 are connected in parallel to the slot lines 10 and 11, the current due to the signal power flows equally through the mixer diodes 4 and 5, and the signal power is well balanced. It is added to mixer diodes 4 and 5 in the same phase.

On the other hand, the branch 9 between the microstrip line and the slot line has an open end instead of the conducting hole 16.
Since it is constructed using a 1/4 wavelength microstrip line 17, the local oscillation power is sent from the local oscillation power microstrip line 6 to the mixer diodes 4 and 5 in the opposite phase as in a conventional mixer. However, the IF power is not coupled to the local oscillation microstrip line 6.

Further, the IF power is extracted from the IF terminal 20 through a low pass filter 14 composed of a thin strip conductor 18 and a high impedance slot line 19.

As described above, when the microwave semiconductor device according to the present invention shown in FIG. 2 is operated as a mixer, signal power is applied directly to the diode from the signal microstrip line 1. Therefore, compared to conventional mixers that have a slot line with a length of about 1/4 wavelength in the signal line, this has the advantage of reduced signal line loss and conversion loss.

Furthermore, since the low-pass filter for separating and extracting the IF power from the microwave power is constructed at the joint between the microstrip line and the slot line, a length of 1/4 wavelength is required. This has the advantage of being able to reduce the number of parts that need to be replaced by one, making the overall size smaller.

In addition, compared to the conventional method, since the conductive hole 16 for connecting the front and back sides of the board is not used, there is no need to drill holes in the board, the high accuracy of the photo etching process is maintained, the processing accuracy is extremely improved, and the characteristics This not only provides a good mixer, but also has the advantage of shortening processing time.

In addition, although the case where the microwave semiconductor device according to the present invention is operated as a mixer has been described above, it is clear that the present invention is not limited to this and can also operate as a phase modulator.

In this case, you can either input the modulation signal to the IF terminal of the mixer, the carrier wave to the signal microstrip line, and obtain the modulated output wave from the local oscillation power microstrip line, or
The input/output terminals are set so that a modulation signal is input to the IF terminal, a carrier wave is input to the local oscillation power microstrip line, and a modulated output wave is obtained from the signal microstrip line.

As described above, according to the present invention, power can be applied from the microstrip line to the two diodes directly connected to the two slot lines, which has the advantage of reducing loss. Since the low-pass filter section is commonly used as the conversion section between the microstrip line and the slot line, there is an advantage that it can be made smaller. Furthermore, since there is no need to drill holes in the base, there is an advantage that the machining accuracy is high and the machining time is short.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conventional mixer, and FIG. 2 is a diagram showing an embodiment of the present invention. In the figure, 1 is a signal microstrip line, 2
is a slot line, 4 and 5 are mixer diodes, and 6 is a slot line.
9 is the microstrip line for local oscillation, 9 is the branch between the microstrip line and the slot line, 1
0 and 11 are slot lines, 14 is a low-pass filter, 15 is an intersection, 16 is a conduction hole, 17 is an open-ended 1/4 wavelength microstrip line, 18 is a thin strip conductor, and 19 is a high impedance slot. line, 20 is an IF terminal. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

Claims (1)

[Claims] 1. Align both ends of the slot line formed of a conductor provided on one side of the dielectric substrate so that they face the same direction, place them close to each other, and make the tips have high impedance, and A first microstrip line having a strip conductor is arranged on the other surface of the main substrate so as to intersect with the tips of the slot lines brought close to each other, and diodes are loaded at the tips of the slot lines, respectively. At the same time, the slot line and the second microstrip line intersect at the middle part of the slot line, and the thin strip conductor is connected to the conductor surrounded by the slot line at the middle part between the diodes. A microwave semiconductor device characterized in that a low pass filter consisting of a conductor and the high impedance slot line is connected to a third line.