JPS6310809A - Resonator - Google Patents

Abstract

PURPOSE:To attain miniaturization, low cost and the improvement of productivity by providing an equivalent circuit where the 2nd capacitor is connected in parallel with an LC series circuit formed by connecting a coil to both sides of the 1st capacitor and forming a capacitor electrode pattern and a coil pattern by the same pattern for both the front/rear sides of the dielectric base. CONSTITUTION:Two capacitor electrode patterns 2a, 2b, 3a, 3b and coil patterns 4a, 5a are formed to a front face 1a and a rear face 1b of a dielectric base 1 respectively. The electrode patterns 2a, 3a and 2b, 3b form capacitors C1,C2. On the other hand, the coil patterns 4a, 5a form to connect the two capacitor electrode patterns 2a, 2b and 3a, 3b on the front/rear side of the dielectric base. Since the coil patterns 4a, 5a form a coil in terms of high frequencies, the equivalent circuit is expressed, where the coils L1, L2 (inductances L1, L2) are connected in series with both sides of the 1st capacitor C1 to form the LC circuit to which the 2nd capacitor C2 is connected in parallel.

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.

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.

On the other hand, the latter type of resonator (stripline) has a large shape when the operating frequency is low, such as the 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 high costs can be avoided. There was a problem that there was no.

In view of these problems, the present invention is small, low cost, and
It is an object of the present invention to provide a useful resonator that can be coupled to each other without using a separate coupling means such as a capacitor when used as a filter.

In order to achieve the above-mentioned object of solving the six points in between, in the resonator according to the present invention, capacitor electrode patterns are formed at two opposing locations on both the front and back sides of a dielectric substrate, and the capacitor electrode pattern and the The first and second capacitors are formed with the dielectric substrate;
A coil pattern is formed between two capacitor electrodes existing on the front surface of the substrate and between two capacitor electrodes existing on the back surface, and is configured by the first capacitor and the coil pattern connected in series on both sides of the first capacitor. The capacitor is characterized in that an LC series circuit is formed with the coil, and the second capacitor is connected in parallel to the LC series circuit.

Figure 1 shows the external configuration of a resonator as an embodiment of the present invention, where Figure (A) is a front view, Figure (B) is a side view, and Figure (C) is a front view.
is a rear view. In the figure, 1 is a dielectric substrate made of, for example, an FRDR material, and its front surface 1a and back surface 1b each have 2
For example, the capacitor electrode patterns 2a, 2b, 3a, 3b and the coil patterns 4a, 5a are formed by screen printing a paste.

The electrode patterns 2a and 3a and 2b and 3b face each other on both sides of the dielectric substrate, forming a capacitor C1°C2 having a capacitance determined by the dielectric constant and thickness of the substrate and the facing area of the capacitor electrodes. On the other hand, the coil patterns 4a and 5a are two capacitor electrode patterns 2a and 2b on each of the front and back surfaces of the dielectric substrate, respectively.

It is formed in a state where 3a and 3b are connected.

Each of the coil patterns 4a and 5a forms a coil in terms of high frequency, so if their inductances are Ll and L2, the resonator has coils LL and L2 on both sides of the first end C1, as shown in FIG. An equivalent circuit is formed by connecting an LC circuit in series with a second capacitor C2 in parallel.

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 4a and 5a have appropriate lengths to enable magnetic coupling with other resonators, and are formed as close to the edge of the substrate as possible.

In addition, two coil patterns 4a in the same resonator,
5a are spaced apart as much as possible so as not to be magnetically coupled or have capacitance.

To make the resonator having the above configuration resonate at fr=504 MHz, for example, if C1 is set as C1=18 pF, LL and L2 are given by the following equations.

Here, if LL=L2, then Ll-L2=2.77nH. C2 can be selected depending on the impedance used, regardless of the resonance frequency.

In this example, when the impedance is 50Ω, C2=
Since Q was maximum at 53pF, I chose 539F.

Here, the dielectric constant ε of the dielectric substrate 1 is 80, and the thickness is 0.4.
11, the capacitance of C1 and C2 is J1=7m嘗, It2=1.5mm, 13=1tm, 14=3,51
Obtained by setting it to 1. Also, the inductance of Ll and L2 is I! This can be obtained by setting 5-1!6=6m. Width W1 of coil patterns 4a and 5a
, W2 are not related to the inductance value, but the larger the width, the smaller the resistance, and therefore the higher the Q, which is preferable. In this embodiment, W1=W2=1.5 m. The resonance characteristics when other betting methods (11°12...16) and the ε and thickness of the dielectric substrate 1 are as described above are shown in the third table.
As shown in the figure.

In this case, a very high value of Q of 148 was obtained.

The reason why such a high Q was obtained is speculation, but it is because the above-mentioned resonator has a unique circuit configuration that has not been seen before in terms of an equivalent circuit, and the fact that the coil patterns 4a and 5
This is thought to be due to the fact that the width of a was increased to lower the resistance, and the dielectric substrate 1 was made of FRDR material.

In the above resonator, the capacitor electrode pattern and the coil pattern are formed in the same pattern on both the front and back surfaces of the substrate. By aligning the patterns on the front and back surfaces in this way, printing masks with the same pattern can be used during manufacturing, resulting in very high productivity.

In addition, in the above embodiment, the dielectric substrate 1 has a thickness of 0°4fi, but by changing the thickness, the capacitance of the capacitors C1 and C2 changes, and the resonant frequency can be changed. An appropriate thickness may be selected depending on the relationship.

According to the present invention, as explained above, a second capacitor is connected in parallel to an LC series 4° circuit in which coils are connected on both sides of a first capacitor.
It is a resonator with a unique equivalent circuit in which two capacitors are connected in parallel, so it has a high Q that is suitable for filters and oscillation elements used at frequencies above 400 MHz.
In addition, compared to conventional methods, less electrode material is required, making it more compact and
Cost reduction can be achieved. In addition, since the capacitor electrode pattern and the coil pattern are formed with common patterns on both the front and back sides of the dielectric substrate, a printing mask with the same pattern can be used during manufacturing, improving productivity. Furthermore, if each coil pattern is formed near the edge of the substrate, by connecting multiple substrates, it is possible to easily magnetically couple the coil patterns of adjacent resonators, making it much easier to install filters than before. Can be configured.

In addition, unlike a dielectric coaxial resonator, the capacitance of the capacitor, which is a component of the resonator, can be changed and adjusted 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. 1(C) is a rear view,
FIG. 2 is a diagram showing an equivalent circuit of the resonator, and FIG. 3 is a diagram showing the resonance characteristics of the resonator. C1...first capacitor, C2...second capacitor, Ll, L2...coil, 1...dielectric substrate,
2a, 2b, 3a, 3b... capacitor electrode pattern, 4a, 5a... coil pattern. Patent applicant Mura Co., Ltd. 1) Factory diagram 2

Claims (1)

[Claims] (1) Capacitor electrode patterns are formed at two opposing locations on both the front and back surfaces of the dielectric substrate, and the electrode patterns and the dielectric substrate therebetween form first and second capacitors; A coil pattern is formed between two capacitor electrodes on the front surface and between two capacitor electrodes on the back surface, and the coil is constituted by the first capacitor and the coil pattern connected in series on both sides of the first capacitor. and forming an LC series circuit, and the second capacitor is connected in parallel to the LC series circuit.