JPS63292807A - Method for adjusting resonance frequency of resonator - Google Patents

Abstract

PURPOSE:To improve the yield of a product by easily enabling a resonance frequency or a central frequency to be adjusted to a lower range by providing a notch on a resonator using a dielectric substrate or the capacitor electrode pattern of a BPF using the resonator. CONSTITUTION:The capacitor electrode patterns 2a and 2b, and 3a and 3b, and coil patterns 4a and 4b are formed on both planes of the dielectric substrate. To adjust the resonance frequency, notch parts A1, A2, B1, and B2 are provided at the connection part of the capacitor electrode pattern and the coil pattern, and also, the inside of the capacitor electrode pattern, on the both surface and rear planes of the dielectric substrate. By providing such notches, coil pattern can be increased, and an inductance L is increased, therefore, the resonance frequency can be lowered. Also, by adjusting the length and the width of the notch, the fine adjustment of the resonance frequency can be performed.

Description

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

Resonators used for filters, oscillation elements, etc. in the above frequency range are required to have relatively strong sharpness (hereinafter referred to as Q), and conventionally such resonators have There are dielectric band shakers, strip lines, etc.

However, both resonators have drawbacks such as relatively high cost, complicated structure, and large size.

Therefore, in order to eliminate these drawbacks, patent application No. 61-097 was filed.
No. 313, a resonator as shown in FIG. 6 has been filed by the present applicant.

That is, in FIG. 6, figure (a) is a front view, figure (b) is a side view, and figure (c) is a rear view. In the figure, 51 is, for example, F
A dielectric substrate made of RDR material or the like, and has two capacitor electrode patterns 52 on its front surface 51a and rear surface 51b, respectively.
a, 52b, 53a.

53b and coil patterns 54a and 55a are formed by screen printing silver paste, for example. The electrode patterns 52a and 53a and 52b and 53b
are opposed on both the front and back surfaces of the dielectric substrate, forming capacitors C1 and C2 having capacities determined by the dielectric constant and thickness of the substrate and the opposing areas of the capacitor electrodes. on the other hand,
The coil patterns 54a and 55a are formed to connect two capacitor electrode patterns 52a and 52b, and 53a and 53b on the front and back surfaces of the dielectric substrate, respectively. Since each coil pattern 54a, 55a forms a coil in terms of high frequency, its inductance is Ll, L2.
Then, as shown in FIG. 7, the resonator is an equivalent circuit in which a second capacitor C2 is connected in parallel to an LC circuit in which coils Ll and L2 are connected in series on both sides of a first capacitor c1.

By the way, in the resonator shown in FIG. 6 above, the capacitance of the capacitors C1 and C2 and the inductance of the coils LL and L2 are determined by the opposing areas, lengths, etc. of the electrode patterns 52a to 55a. , the resonant frequency is uniquely determined.For this reason, if there are variations in pattern printing, carbonization, substrate thickness, etc., the resonant frequency will also be affected by this and will vary from resonator to resonator, making it difficult to achieve the desired resonant frequency. This has caused problems in terms of product yield in that it is difficult to obtain

The present invention has been made in view of the above-mentioned problems, and provides a reasonable method for adjusting the resonant frequency in order to manufacture a resonator having the above-described structure with a high yield.

In order to achieve the above-mentioned object of improving the balance, the present invention includes a capacitor electrode pattern formed at two opposing locations on both the front and back sides of a dielectric substrate, and a capacitor electrode pattern formed between the electrode pattern and the dielectric substrate in between. 1. A second capacitor is formed between two capacitor electrodes on the front surface of the substrate and a second capacitor on the back surface of the substrate.
A coil pattern is formed between two capacitor electrodes,
The first capacitor and the coil formed by the coil pattern connected in series on both sides of the first capacitor form an LC.
In a resonator forming a series circuit and in which the second capacitor is connected in parallel to the LC series circuit, at least one notch is provided inside the capacitor electrode pattern at a connection portion between the capacitor electrode pattern and the coil pattern. It is characterized by having the following.

Figure 1 shows a resonator which is an embodiment of the present invention, but Figure 6 shows a resonator according to an embodiment of the present invention.
The basic structure is almost the same as that of the conventional resonator shown in the figure, and uses both the front and back surfaces of the dielectric substrate, and the capacitor electrode patterns 2a, 'lb and 3a, 3b and the coil pattern 4a.
, 4b.

Here, the difference from the conventional example is that in order to adjust the resonant frequency, there are cut portions AI, A2. The point is that Bl and B2 are provided on both the front and back sides of the dielectric substrate. In the figure, solid lines indicate the front surface pattern, and dotted lines indicate the back surface pattern. Also, the dimensions of each part are as follows.

a=4.5 (fl), b=7.0 (@l).

c=1.0 (m), d=1.0 (m).

e=2.2 (wl), f=1.0 (fl).

g = 0.1 (M), w = 0.5 (am) By providing this cut, the coil pattern becomes long (increasing the inductance L, and as a result, the resonance frequency decreases).

Furthermore, by adjusting the length and width of this cut, the resonance frequency can be finely adjusted. In the figure, the above cut is 4
Location A1. Although it is provided at A2, Bl, and B2, it is sufficient to simply cut any one of them. The method for cutting this cut may be mechanical or laser trimming. This cut is made from the inside to the outside as shown in the figure, and may be made diagonally or not on an extension of the coil pattern. FIG. 2 shows a frequency characteristic curve when the resonator shown in FIG. 1 is provided with a notch.

In the figure, curve 1 shows the case where there is no cut, and curve 2 shows the cut size h (h
=0. Curve 3 shows the case where 5m5) is provided, and curve 3 is the case where cuts are made at 4 locations in A and B in the figure shown above the graph.
(h=0.5mm) is shown.

It can also be seen from this curve that when a notch is provided, the resonance frequency shifts to a lower side.

Next, FIG. 3 shows a front view (a) and a side view (b) when the frequency adjustment method is applied to a bandpass filter.

The figure shows that two of the resonators shown in FIG. 1 (hereinafter referred to as Ql and Q2) have two coil patterns 39.40.
An example is shown in which the distances are set close to the distance k. Since the two coil patterns 39 and 40 are close to each other, inductive coupling occurs between them, forming a bandpass filter having an equivalent circuit as shown in FIG.

In Figure 3, 31 is an input terminal, 32 is a ground terminal,
33 is an output terminal, 34 is a dielectric substrate, 35 is a back electrode shown by a dotted line, 36 is a front electrode shown by a solid line, and 37 and 38 are cut portions.

In FIG. 4, M is the mutual inductance that represents the degree of magnetic coupling between the two coil patterns 39, 40, L12. L
14 is the inductance of the lead wires 32 and 32. Note that since the two resonators described above use the dielectric substrate 34, not only magnetic coupling but also capacitive coupling is performed. In the figure, Cs schematically represents the coupling capacity.

Here, the method for adjusting the center frequency of the bandpass filter shown in FIG. 3 is to provide a notch in the capacitor electrode pattern, similar to the resonator described above.

In addition, when providing a notch, both resonators Ql.

It is preferable to cut the same amount at the same position in the 02 portion, because if only one resonator is provided with a cut, the resonance waveforms of the two resonators will be different.

On the other hand, if the same position of the two resonators is removed by the same amount,
The sameness of the resonance waveforms of the two resonators can be maintained, and therefore only the center frequency can be shifted while maintaining the sameness of the filter characteristic curves before and after the notch is provided.

Figure 5 shows the frequency characteristic curve of the bandpass filter.
In the figure, curve 1 indicates the case where no notch is provided, and curve 2 indicates the case where the notch is provided at the A and B portions of the filter shown above the graph.
(h=0.50) is shown. As can be seen from FIG. 5, this is achieved by providing notches in the capacitor electrode pattern.

This allows the center frequency to be lowered.

In the bandpass filter shown in Fig. 3, the two resonators Ql and Q2 are cut at the same position, but at the stage of manufacturing the bandpass filter, it was found that the resonance waveforms of the two resonators were different. In some cases, in order to adjust the resonance waveform, cuts may be provided only in the capacitor electrode pattern of one resonator.

As explained above, according to the present invention, the resonant frequency or center frequency can be adjusted by providing notches in the capacitor electrode pattern of a resonator using a dielectric substrate or a bandpass filter using this resonator. It was possible to easily adjust the value to a lower value, which had the effect of improving product yield.

[Brief explanation of the drawing]

Fig. 1 is a front view of a resonator which is an embodiment of the present invention, Fig.
The figure shows the frequency characteristic curve when notches are provided in the capacitor electrode pattern of the resonator shown in Fig. 1, Fig. 3 shows the front view (a) and side view (b) of the bandpass filter, and Fig. 4 shows the frequency characteristic curve of the bandpass filter. The equivalent circuit of the bandpass filter shown in the figure, Figure 5 is the frequency characteristic curve of the bandpass filter, Figure 6 (A) is a front view of a conventional resonator, (B) is a side view, (C) is a rear view, FIG. 7 shows an equivalent circuit diagram of the resonator of FIG. 6. l... Dielectric substrate, 2a, 2b... Capacitor electrode pattern, 3a, 3b... Capacitor electrode pattern,
4a, 4b...Coil pattern, 31...Input terminal, 32...Earth terminal, 33...Output terminal, 34...
...Dielectric substrate, 35...Back electrode, 36...Top electrode, 37.38...Notch portion, 39.40...Coil pattern. Patent Applicant 2 Murata Manufacturing Co., Ltd. Figure 1 8. ■X6. ■X O, 33 (+m) Figure 3 Figure 4 Figure 6

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 in which the second capacitor is connected in parallel to the LC series circuit, the resonator includes at least a portion at the connection portion between the capacitor electrode pattern and the coil pattern on the inside of the capacitor electrode pattern. A method for adjusting the resonant frequency of a resonator, characterized by providing one notch.