JPS6348902A - Matching type diode circuit - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a matched diode circuit including a pin diode that operates with reverse bias in a microwave band.

[Conventional technology]

Figure 2 shows a matching diode circuit, described in Alpha Catalog P3-18, for example, in which pin diodes are connected in parallel and operated in reverse bias, where (a) is an equivalent circuit diagram and (b) is an implementation example. The figure shown, tc) is a Smith chart diagram showing a matching state. In the figure, numeral 1 is a carrier, 2 is a microstrip line, 3 is a pin diode mounted on the carrier 1, and 4 is a gold wire connecting the microstrip line 2 and the pin diode 3.

In this matching diode circuit, the pin diode 3 becomes capacitive when operated with a reverse bias, and the gold wire 4 connecting the microstrip line 2 and the pin diode 3 has an inductance component in the microwave band. Therefore, as shown in the Smith chart diagram in FIG.
Then, due to the capacitance component of pin diode 3, point B = C
point, and due to the inductance component of the gold wire 4, c
Returning to point -A, a matching circuit is formed by the inductance of the gold wire 4 and the capacitance of the pin diode 3.

[Problem that the invention seeks to solve]

Since the conventional matching diode circuit is constructed as described above, the inductance of the gold wire increases as the frequency increases, and if the capacitance of the pin diode is insufficient, the matching will shift. Furthermore, if the capacitance of the pin diode differs, the capacitance of the gold wire must be changed each time, and variations in the way the gold wire is stretched and variations in the capacitance of the pin diode cause mismatching, increased loss, and voltage There were problems such as poor standing wave ratio (V, S, W, R1).

This invention was made to solve the above-mentioned problems, and can reduce mismatching even in high frequency bands, and correct mismatching caused by variations in the capacitance of pin diodes and variations in the inductance component of gold wires. The purpose of this invention is to obtain a matched diode circuit that can perform the following steps.

[Means for solving the problem] A matching diode circuit according to the present invention is configured by adding a capacitive component such as a stub to a microstrip line to configure a low-pass filter matching circuit. be.

[Effect]

In this invention, since a capacitive component such as a stub is added to the microstrip line, impedance matching of the circuit can be achieved by changing the capacitance of the capacitive component.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a matched diode circuit according to an embodiment of the present invention, (a) is an equivalent circuit diagram, (bl is a diagram showing a mounting example, and (C1 is a Smith chart diagram showing a matching state. 1 to 4 are the same as in FIG. 2, and 5 is a capacitive stub, which forms part of the matching circuit.

In a matched diode circuit configured like this, 50
The radio waves propagating through the Ω Microstri-Knob line 2 are
As shown in the Smith chart in Figure 1 (C1), the inductance component of the gold wire 4 causes the transition from point A to point B, and the capacitance component of the pin diode 3 causes the transition of the gold wire 4 from point A to point C.
The inductance component causes the 0 point to the 0 point, and the capacitive stub 5 returns to the D point to the B point, forming a matching circuit.

That is, as the frequency increases, the inductance component of the gold wire 4 increases, so in the conventional circuit, the rotation from point A to point B and point C = point A becomes significant due to the series inductance component, and eventually Since the position is at point D shown in Figure 1, the misalignment in matching becomes significant, but in this example circuit, the capacitive stub 5 is added, so by rotating from point D to point B, the above-mentioned matching can be achieved. By correcting the deviation and achieving matching, and by changing the capacitance of the capacitive stub 5, the circuit can be matched even if there are variations in the capacitance of the pin diode 3 and variations in the inductance component of the gold wire 4. can be taken. It should also be possible to further reduce the insertion loss of the circuit and improve the voltage standing wave ratio.

In the above embodiment, the case where the capacitive stub 5 is realized by an oven stub is shown, but this capacitive stub is
A similar effect can be obtained even if the length is 4 or more and a short stub is used. In this case, the pin diode 3 is floated in a DC manner with a capacitor, and the short stub is used as a DC return. With this circuit configuration, there is no need for a DC block capacitor on the signal line. However, there is an effect that loss in layers and circuits can be reduced.

〔Effect of the invention〕

As described above, according to the matched diode circuit of the present invention, since a capacitive circuit is added to the microstrip line, it is possible to reduce mismatching at high frequencies, and also to reduce variations in the capacitance of the pin diode and the inductance component of the gold wire. It has the effect of being able to control and achieve consistency.

[Brief explanation of the drawing]

FIGS. 1(a) and (g)) are diagrams showing an equivalent circuit diagram and a mounting example of a matched diode circuit according to an embodiment of the present invention, and FIG. 1(C) is a Smith's circuit diagram showing a matching state of the above embodiment. Chart diagram, Figure 2 (a) and crest) are diagrams showing an equivalent circuit diagram and mounting example of a conventional matched diode circuit, Figure 2 (C
1 is a Smith chart diagram showing a matching state in a conventional example. In the figure, 1 is a carrier, 2 is a microstrip line, 3 is a pin diode, 4 is a gold wire, and 5 is a capacitive stub. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) A matching diode circuit comprising a pin diode connected to a microstrip line via a gold wire, including a capacitive circuit added to the microstrip line and constructed using the line material. A matched diode circuit featuring: