JPS5943841B2 - Impedance matching device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a circuit device for matching the impedance of a circuit element taken out in the form of a microstrip line with a signal source impedance or a load impedance.

The method conventionally used to realize impedance matching of circuit elements taken out in the form of a microstrip line is to create discontinuities in a portion or multiple places of the upper conductor 1 of the microstrip line, as shown in Figure 1a. However, impedance matching is achieved by providing a stub 2, by providing a thick line part as the characteristic impedance change point 3 as shown in Figure 1 to lower the impedance, or by providing a constriction to increase the impedance. , This format has the disadvantage that it is not easy to change the external impedance of the element continuously and over a wide range when the impedance of the circuit element is unknown or when the element impedance changes depending on the magnitude of the signal. there were.

In Fig. 1 a, t), 4 is a ground conductor, 5 is a microstrip substrate made of an insulator, and 6 is an upper conductor 1.
This is an element such as a diode connected to the

In order to solve these drawbacks, the present invention creates a hole in the ground conductor of the microstrip line, inserts a short-circuit end into the hole, and continuously changes the position of the short-circuit end.
No. 71 provides an impedance matching circuit that adds a necessary actance component to an external circuit of an element.

The present invention will be described in detail below using the drawings.

FIG. 2 shows an embodiment of the present invention, in which a waveguide 1 is provided on the ground conductor 4 of the microstrip line in order to match the impedance of the element 6 connected to the microstrip line with the signal source impedance. A short piston 8 is inserted therein to adjust the position of the short end 9.

FIG. 3 is an equivalent circuit of the embodiment shown in FIG.

As an example, the characteristic impedance Z of a microstrip line.

= signal source impedance R8, and the real part R of the element impedance Zd = Zo. In order to realize impedance matching, the imaginary part The electrical length θ is set so that it is equal to .

Generally, it is RZo, so in this case, three waveguides 1 are provided as shown in Fig. 4, or one waveguide 1 is used as shown in Fig. 5 to measure the imaginary part of the element impedance. The impedance matching is realized by canceling the real part by adopting the configuration shown in FIG. 1 of the conventional method, for example, a transformer structure.

In this case, x=x'. The present invention can also be applied to a shielded microstrip line or triplate line as shown in FIG. 6, and in this case, waveguides T are provided above and below the center conductor 1a.

As explained above, the present invention can add external circuit resistance over a wide range from - (material) to +■ by continuously changing the position of the short piston using a plunger, and This method has the advantage that impedance matching can be performed more easily and more precisely than the conventional method.

Application examples include frequency multipliers using diodes and matching devices for FET amplifiers in frequency bands where waveguides are easy to manufacture, such as quasi-millimeter wave bands and millimeter wave bands.

[Brief explanation of the drawing]

i1 Figures a and b are perspective views showing an example of a conventional impedance matching device, Figure 2 is a perspective view showing an embodiment of the present invention, and Figure 3 is a perspective view showing an example of a conventional impedance matching device.
The figure is an equivalent circuit of the embodiment shown in FIG. 2, and FIG. 4 is a perspective view showing an embodiment of the present invention in which the impedance of the element is arbitrary.
FIG. 5 is a perspective view and an equivalent circuit showing another embodiment of the present invention, and FIG. 6 is a perspective view showing an embodiment of the present invention in the case of a shielded microstrip line or triplate line. 1... Upper conductor, 1a... Center conductor,
2... Stub, 3... Impedance change point, 4... Ground conductor, 5... Microstrip board, 6... Element, T...
...Waveguide, 8...Short piston, 9...
...Short end.

Claims (1)

[Claims] 1 A waveguide in which a short-circuit end is inserted in the ground conductor of the microstrip line in a direction perpendicular to the signal propagation direction when matching the impedance of a circuit element taken out in the form of a microstrip line with the signal source impedance or load impedance. An impedance matching device characterized in that impedance matching is realized by adding a reactance to an external circuit of an element by providing a position of the short-circuited end within the waveguide so as to be able to change continuously.