JPS62120102A - Ring type microstrip line resonator circuit - Google Patents

Abstract

PURPOSE:To prevent the deterioration in the Q of the resonance circuit and to easily adjust the resonance frequency by widening a part of width of a microstrip line and providing a slit for adjusting the width or length to the widened part. CONSTITUTION:Since the ring type microstrip line resonance circuit has a potential close to that of a resonance capacitor 7, the current short-circuit mode is obtained at the middle part 3a of the microstrip line 3. Thus, the conductor resistance is lowered by widening the width of the part to prevent the reduction in the Q and to increase it further. The adjustment of the line width is realized by disconnecting or connecting a width adjustment slit 8.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention is a ring type micros used in high frequency circuits.
This relates to an IJ tube line resonant circuit.

Conventional technology Ring type micros l-IJ tube line resonant circuit (hereinafter referred to as
RMSR (abbreviated as RMSR) is an important circuit element in high frequency circuits and is used in filter circuits, oscillators, etc. In particular, determining the resonance frequency of RMSR is an important issue. As a method devised to solve this problem, for example, there is a band-pass filter using RMSR disclosed in Japanese Patent Publication No. 54-42574. below,
A conventional RMSR will be explained with reference to FIG.

In Fig. 4, l is an input/output coupling capacitor, 2 is a DC blocking capacitor, 3 is a microstrip line, and 4
is a varactor diode for resonant frequency adjustment, 5.5' is a resistor and RFC that applies DC voltage to varactor diode 4,
6 is an RFC that determines the DC potential applied to the varactor diode 4.

The operation of the above configuration will be explained below.

First, a DC potential is applied to the varactor diode 4 by the resistor 5 and RFC 6, and a constant varactor capacitance is obtained. This varactor capacitor and microstri.

A parallel resonance type resonant circuit is constituted by the microstrip line 3, and its resonant frequency is determined by the capacitance of the characteristic varactor diode 4 of the microstrip line 3. The varactor capacitance changes depending on the DC potential applied to the varactor diode 4, making it possible to adjust the resonant frequency of the resonant circuit.

Problems to be Solved by the Invention However, since the configuration described above uses a varactor diode for frequency adjustment, there is a problem in that the Q factor inevitably decreases and the characteristics as a resonant circuit deteriorate.

The present invention solves the above-mentioned problems of the prior art, and aims to prevent Q deterioration of a ring-type microstrip line resonant circuit and to easily adjust the resonant frequency. It is.

Means for Solving the Problems The present invention widens a part of the microstripe line of a ring-type microstripe IJ tube line resonant circuit, and provides a slit for width or length adjustment in that part. By doing so, the above objectives are achieved. .

Effects The present invention has the above-mentioned configuration, and by adjusting the pickpocket/1·, it is possible to adjust the resonant frequency without lowering the Q of the resonant circuit.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view of a ring type microtubular line resonant circuit in a first embodiment of the present invention.

In Fig. 1, 1 is a capacitor for input/output coupling, 7 is a capacitor for resonance, 3 is a microslip line with a wide central portion 3a, and 8 is installed in the wide central portion. d] Adjustment slots.

In the above configuration, its functions will be explained below using FIG. 2.

The ring-type microstrip line resonant circuit shown in Fig. 2(a) has two
As shown in Figure (C), the difficulty of equivalent expansion can be compared.

The circuit in Figure 2 (C) generally has impedance: Z2 (Z
l+ jZo tonβl)/(Zo + jZltQ
It is expressed as nβg)xZo. (However, β: phase constant, Z1 division capacitance l: microstrip line length, ZO: characteristic impedance). Also, if we consider other divided capacitances as Zi, the resonance condition is ZiZi −0
Then Zi = j (Zo a tqnβ/-Zl)
/(1+ZltQnβl). From the above, it is clear that the resonant frequency is determined by the dividing capacitance and the microstrip line length1.If the configuration of Figure 1 is expanded in the same way, Figure 2 ((like 11)') shows that this microstrip line length 7"
] The output line 3 is represented by the following equation.

Z=(K(1-tQnθ')(1-tcinθ2)-2
(2 on 1+).

θ1@[Mθ2)/'Y2・2(K・θ1+乍θ2)(K−1llnθ1−tqnθ2) (In addition, θ1 and θ2 are the electrical length of the microstrip line 3 and the corresponding line impedance, respectively. Zl,
In Z2, the domimeter/pass is Yl, and the impedance ratio of Y2 is: Z2/Z1-Yl/Y2. ) However, the impedance of the mital strip line 3 is determined by the line width. Therefore, by changing the three widths of the microstrip line shown in Figure 1 with slits 8,
The resonance frequency can be adjusted.

Now, since the ring type microstrip line resonant circuit shown in FIG. Therefore, by widening the width of this portion, the conductor resistance is reduced, and the Q can be prevented from decreasing and further improved. Adjustment of the width of the temple line can be realized by separating or connecting the width adjusting slit 8 shown in FIG.

Next, a second embodiment of the present invention will be described.

FIG. 3 is a plan view of a lymph type microstrip line resonant circuit according to a second embodiment of the present invention. This is because a microstrip line slit 8 for adjusting the width is provided.

In the above configuration, it is obvious that as in the first embodiment, when the line width direction changes, the impedance Z of the microstrip line 3 changes and the resonant frequency changes.

This characteristic can be used to adjust the resonant frequency of a ring-type microstrip line resonant circuit.

In addition, in the first embodiment shown in FIG. 1, the width of the slit 8 in the microstrip line 3 is made variable, and in the second embodiment, the same length is made variable, but the width and length are adjusted at the same time. You can do it like this.

Furthermore, in the first and second embodiments of the present invention, the input/output coupling capacitor 1 was used for the input and output of the circuit, but
A coupled line or the like may be used as the input/output connection.

Effects of the Invention As described above, the present invention can easily adjust the resonant frequency by changing the width of a part of the microstrip line, providing a slit there, and changing the width or length using the slit. can be varied, and furthermore, the no-load Q of the circuit is not reduced, which has a great effect.

[Brief explanation of drawings]

FIG. 1 is a plan view of a ring-type microstrip line resonant circuit according to the first embodiment of the present invention, FIG. 2 is an equivalent circuit diagram of the same ring-type microstrip line resonant circuit, and FIG.
This figure is a plan view of a ring type microstrip line resonant circuit according to a second embodiment of the present invention, and FIG. 4 is a plan view of a conventional ring type microstrip line resonant circuit. DESCRIPTION OF SYMBOLS 1... Capacitor for input/output coupling, 2 Capacitor for direct current blocking, 3... Microstrip line, 4... Varactor diode for adjusting resonance frequency, 5... Resistor for applying DC voltage, 6... RFC17...・Resonance capacitor,
8...Microstrip line pickpocket for width adjustment. [・. Name of agent: Patent attorney Toshio Nakao
2nd side No. J, figure slip F, 3eI snoring (jikenko
↓ Go

Claims (2)

[Claims] (1) comprising a capacitive means for resonance and a ring-shaped microstrip line connected in parallel to the capacitive means,
A ring-type microstrip line resonant circuit in which a part of the microstrip line is widened to provide a slit. (2) A ring-type microstrip line resonant circuit according to claim 1, characterized in that a slit for length adjustment is provided in a wide portion of the microstrip line width.