JPS6310810A - Resonator - Google Patents

Abstract

PURPOSE:To form a filter with simple structure by forming two nearly parallel coil patterns on one major surface of a base and using two capacitors to connect ends of the coil patterns. CONSTITUTION:The coil patterns 2, 3 are formed by applying screen printing of, e.g., silver paste, while chip capacitors are used for the 1st and 2nd capacitors 4, 5. The chip capacitors 4, 5 are connected to the coil patterns 2, 3 by solder. Since the coil is formed to the ends of coil patterns 2, 3 in terms of high frequencies' the resonator is expressed as an eqivalent circuit where the LC series circuit connecting coils (inductances L1, L2) in series across the 1st capacitor C1 is connected in parallel with the 2nd capacitor C2.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a resonator suitable for filters and oscillation elements used in frequency ranges including and exceeding the UHF band.

5 Problems with Conventional Resonators used for filters, oscillation elements, etc. in the above frequency range are required to have relatively high sharpness (hereinafter referred to as Q), and as such resonators, Conventionally, there are dielectric resonators, strip lines, etc.

However, the former type of resonator (dielectric coaxial resonator) is relatively expensive, and when used as a filter, simply arranging them in parallel does not constitute a circuit, and requires a separate coupling means such as a capacitor. However, there were problems in that the structure was complicated and large, and the assembly work was time-consuming.

In addition, the latter type of resonator (strip line) has a thick shape when the operating frequency is low, such as 400 MHz band, and on top of that, since electrodes are formed on the entire back surface of the substrate, there are many electrode members, and the cost is high. There were problems that could not be avoided.

In view of these problems, the present invention is small, low cost, and
The object of the present invention is to provide a useful resonator that is easy to impedance match and has a predetermined high Q.

A resonator according to the present invention for achieving the above object has two substantially parallel coil patterns formed on one main surface of a substrate, and an end portion of the coil pattern. They are connected to each other by two capacitor parts.

Figure 1 shows the external configuration of a resonator as an embodiment of the present invention. It consists of a pair of coil patterns 2.3 formed in a shape, and first and second capacitor parts 4.5 connected to the ends of the coil patterns 2, 3.

Specifically, the coil pattern 2.3 is formed, for example, by screen printing silver paste;
The first and second capacitor parts 4.5 use chip capacitors.

The chip capacitor component 4.5 is connected to the end of the coil pattern 2.3 by soldering. Each of the coil patterns 2.3 forms a coil in terms of high frequency, so if their inductances are Ll and L2, the resonator has coils LL and LL on both sides of the first capacitor C1, as shown in FIG. A second LC series circuit in which L2 is connected in series
The capacitor C2 is connected in parallel to form an equivalent circuit.

A resonator with such an equivalent circuit has not existed in the past, and therefore it can be said that it is a new resonator in terms of the equivalent circuit. The two coil patterns 2 and 3 have appropriate lengths to enable magnetic coupling with other resonators, and are preferably formed as close to the edge of the substrate as possible. Further, it is desirable that the two coil patterns 2.3 in the same resonator are separated as much as possible so as not to be magnetically coupled to each other or have electrostatic capacitance. The illustrated example is implemented in the most distant state.

FIG. 3 shows the frequency characteristics of the resonator having the above configuration. The method of selecting the substrate and coil pattern to obtain this characteristic is as follows.

(A) Substrate: 9X7 (m) Thickness 0.8 (1 layer) Magnetic permeability μ = 60 (B) Coil pattern 2 β1 = x2 = 8.0 (Tsuru) W1
=W2= 1.5 (u) (c) Capacitor: C1-18 (pF) C2=43
(pF) In this case, a very high value of Q of 130 was obtained.

The reason why such a high Q was obtained is speculation, but the reason is that the above resonator has a unique circuit configuration that has not been seen before in terms of equivalent circuit, and that the width of the coil pattern 2.3 is widened. This is thought to be due to the lowering of the resistance bone.

In addition, in the above embodiment, since the substrate is made of ferrite, which is a ferromagnetic material, the inductance of the coil pattern is larger than that when the substrate is made of other materials. The length of the coil pattern needed to obtain this is short, and the resonator can be made smaller accordingly. It should be noted that the present invention is not limited to the above-mentioned embodiments (the design can be changed without departing from the scope of the invention, and although illustration is omitted, a capacitor with leads may be used instead of a chip capacitor on the substrate 1.
You are also free to install it on your computer.

Also, as explained above, according to the present invention, a resonance circuit having a unique equivalent circuit in which a second capacitor is connected in parallel to an LC series circuit in which coils are connected on both sides of a first capacitor is provided. Since it is a device, it has a high Q suitable for filters, oscillation elements, etc. used at frequencies of 400 MHz or higher, and requires less electrode material than conventional ones, achieving a low cost Bt-6. Also, 1st. Since the second capacitor uses a capacitor component, a ferrite substrate can be used as the substrate, and the resonator can be made smaller. Furthermore, if each coil pattern is formed near the edge of the board,
By connecting a plurality of substrates, magnetic coupling can be easily achieved, which has the remarkable effect of making it possible to form a filter with an extremely simple structure compared to conventional filters.

In addition, unlike a dielectric coaxial resonator, by replacing the capacitor that is a component of the resonator, the capacitance can be changed independently, making impedance matching easier.

[Brief explanation of drawings]

FIG. 1(a) is a front view showing a resonator as an embodiment of the present invention, FIG. 1(b) is a side view, FIG. 2 is a diagram showing an equivalent circuit of the resonator, and FIG. 3 is a diagram showing an equivalent circuit of the resonator. FIG. 3 is a diagram showing resonance characteristics of the resonator. 1... Board, 2.3... Coil pattern, 4.5.
...Capacitor parts. Patent applicant Murata Manufacturing Co., Ltd. Figure 1

Claims (2)

[Claims] (1) A resonator characterized in that two substantially parallel coil patterns are formed on one main surface of a substrate, and the ends of the coil patterns are connected to each other by two capacitor parts. . (2) The resonator according to claim (1), wherein the substrate is made of ferrite.