JPH0434286B2 - - Google Patents

Description

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

Prior Art Resonators used in filters, oscillation elements, etc. in the above frequency range are required to have relatively high sharpness (hereinafter referred to as Q), and such resonators have conventionally been made using dielectric materials. There are coaxial resonators, strip lines, etc. However, these resonators have complicated structures and are large in size.
There was a problem with the high cost.

Therefore, in order to solve these problems, the applicant of the present invention first proposed a small and low-cost resonator as described below (Japanese Patent Application No. 61-97312).

This resonator consists of a substrate 11 as shown in FIG.
Coil patterns 12a and 13a are provided on the front surface 11a and back surface 11b of the , and two capacitor electrode patterns 14a, 14b, 15a, and 15a are provided on both ends thereof, respectively.
15b are formed. This capacitor electrode pattern is 14a and 15a and 14b and 15b.
are opposed on both the front and back surfaces of the substrate 11,
They form capacitors C11 and C12. Further, the coil patterns 12a and 13a form a coil in terms of high frequency.

Problems to be Solved by the Invention By the way, in the above configuration, the dielectric constant ε of the substrate 11
Using a resonator with a thickness of 80 and a thickness of 400 μm, fr=
To resonate at 504MHz, the capacitance of capacitor C is C11 = 18PF, C12 = 53pF, and the inductance of the coil is L11 = L12 = 2.77nH. In order to obtain these values, capacitor electrode patterns 14a, 14b, 1 constituting capacitors C11 and C12 are
5a, 15b, l11=7mm, l12=1.5mm, l13=
The coil patterns 12a and 13a forming the coil are formed to a size of 7 mm, l14 = 3.5 mm, and l15
= l16 = 6.0 mm, and compared to dielectric coaxial resonators, strip lines, etc., this resonator had a simple structure and could be made smaller.

However, in recent years, there has been a strong demand for smaller and lighter electronic equipment bodies, and the resonators described above still pose an obstacle to making the equipment bodies smaller and lighter.

In view of these problems, it is an object of the present invention to provide a resonator that is even smaller and lower in cost.

Means for Solving the Problems In order to achieve the above object, a resonator according to the present invention includes a substrate, two coil patterns formed on the surface of the substrate, and a substrate extending from both ends of both coil patterns. Four capacitor electrode patterns formed on the surface, and two capacitor electrode patterns formed inside the substrate facing both the capacitor electrode pattern extended from one coil pattern and the capacitor electrode pattern extended from the other coil pattern. Its structural feature is that it consists of a capacitor electrode pattern.

According to the above structure, since the capacitor electrode pattern constituting the capacitor is formed inside the substrate, it is possible to reduce the facing distance between the capacitor electrode pattern formed on the surface of the substrate and the capacitor electrode pattern formed inside the substrate. By placing them close together, the capacitor capacity increases. Therefore, if the capacitors have the same capacity, the area of the capacitor electrode pattern can be reduced, and a pair of coils and two capacitors can be electrically coupled as desired. resonator circuit can be obtained.

Embodiment FIG. 1 shows a resonator as an embodiment of the present invention, in which figure A is a front view and figure B is a sectional view taken along the line X-X in figure I. In the figure, 1 is a board, specifically
Showing a dielectric substrate made of FRDR material etc., surface 1a
Two coil patterns 2a and 3a are formed in parallel. And both coil patterns 2a,
At both ends of 3a, capacitor electrode patterns 4a,
4b, 5a, and 5b are formed. Coil patterns 2a, 3a and capacitor electrode pattern 4
a, 4b, 5a, and 5b are formed, for example, by screen printing silver paste.
In the interior 1b of the substrate 1, capacitor electrode patterns 6a and 7a for forming a capacitor are formed at a distance d from the surface 1a, facing the capacitor electrode patterns 4a and 5a and 4b and 5b, respectively. This capacitor electrode pattern 6
A and 7a can be formed by a lamination method used for forming internal electrodes of multilayer capacitors. The capacitor electrode patterns 4a, 5a
and the capacitor electrode pattern 6a, and the capacitor electrode patterns 4b and 5b and the capacitor electrode pattern 7a are configured to face each other as described above. form capacitors C ₃ , C _{4 ,} C ₅ , C ₆ with _capacitances determined by
are connected in series to form a first capacitor C1, and at the same time, capacitors _C5 and _C6 are connected in series to form a second capacitor C2.
Also, since the coil patterns 2a and 3a form a coil in terms of real frequency, if their inductances are L1 and L2, this resonator is located on both sides of the first capacitor C1, as shown in FIG. It is represented by an equivalent circuit in which a second capacitor C2 is connected in parallel to an LC series circuit in which coils L1 and L2 are connected in series. In addition, two coil patterns 2a and 3a
It is preferable that the coil patterns 2a and 3a have an appropriate length to enable magnetic coupling with other resonators, and should be formed as close to the edge of the substrate as possible. It is desirable to space them apart as much as possible so that they are not magnetically coupled or have capacitance.

The above equivalent circuit is a circuit configuration in which lead wires are connected to both sides of the second capacitor. For example, if the lead wire is connected to the center of the coil, the coils are connected in series on both sides of the capacitor. It is also possible to construct a circuit by connecting things in parallel.

To make the above resonator resonate at fr=504MHz,
For example, if C1=18pF, L1 and L2 are given by the following equations.

Here, if L1=L2, then L1=L2=2.77nH. C2 can be selected depending on the inductance used, regardless of the resonance frequency. In this example, when the inductance is 50Ω, C2
= 53pF has the maximum Q, so I chose 53pF.
Here, if the dielectric constant ε of the substrate 1 is 80 and the distance d is 20 μm, the capacitance of C1 and C2 is l1=l2=l3=
This is obtained by setting l4=2mm, l5=l7=0.26mm, and l6=l8=0.61mm. Further, the inductances of L1 and L2 are obtained by setting l9=l10=6.0 mm. Coil patterns 2a, 3a
The widths W1 and W2 of W1 and W2 are not related to the inductance value, but the larger the width, the smaller the resistance.
Q is high, which is preferable. In this example, W1
=W2=1.5mm. The resonance characteristics of the resonator formed with the above dimensions are shown in FIG. 3, and in this case, a very high value of Q of 148 was obtained.

As mentioned above, in the resonator of this example, the distance between the capacitor electrode patterns is 1/20 that of the resonator shown in the conventional example (this example: conventional example = 20 μm:
400 μm), so if the capacitor capacitance is the same, the area occupied by the capacitor electrode pattern can be reduced to 1/20 (however, in this example, capacitors C ₃ , C ₄ and C ₅ , C ₆ are Since they are connected in series, the area is 1/10.) Therefore, the volume of the resonator itself is significantly reduced, which has a great effect on miniaturizing the resonator.

Note that in the above embodiment, the capacitor electrode patterns 6a and 7a buried inside the substrate 1b were provided at a distance d from the surface, but changing the distance d changes the capacitance of the capacitors C1 and C2 and changes the resonance frequency. Therefore, it is possible to set an appropriate value in relation to the frequency used.

Effects of the Invention As explained above, in the resonator according to the present invention, one of the capacitor electrode patterns constituting the capacitor is buried inside the substrate, so if the capacitor capacitance is the same, the area occupied by the capacitor electrode pattern is Since it can be made small, the volume of the resonator itself can be reduced, contributing to the miniaturization of electronic devices that use this resonator, and it also has a high Q that is suitable for filters and oscillation elements used at frequencies above 400 MHz. Moreover, less electrode material is required than in the past, and costs can be reduced.

In addition, since the capacitor electrode pattern is embedded inside the substrate, even though the distance between the capacitor electrode pattern formed on the surface of the substrate and the capacitor electrode pattern formed inside the substrate is narrowed,
Since there is no need to reduce the thickness of the substrate, the strength of the substrate can be maintained in a strong state.

Furthermore, when connecting a lead wire to this resonator, it can be done only on the front surface side of the board, making it easy to attach it to a printed circuit board or the like.

[Brief explanation of drawings]

FIG. 1A is a front view showing a resonator as an embodiment of the present invention, FIG. 1B is a sectional view taken along line X-X of FIG.
Fig. 2 is a diagram showing an equivalent circuit of the resonator, Fig. 3 is a diagram showing the resonance characteristics of the resonator, Fig. 4 A is a front view showing a conventional resonator, and Fig. 4 B is a side view. ,
FIG. 4C is a rear view. 1... Board, 2a, 3a... Coil pattern,
4a, 4b, 5a, 5b... capacitor electrode pattern, 6a, 7a... capacitor electrode pattern,
C1, C2... Capacitor, L1, L2... Coil.

Claims (1)

[Claims] 1. A substrate, two coil patterns formed on the surface of the substrate, four capacitor electrode patterns extending from both ends of both coil patterns and formed on the surface of the substrate, and from one coil pattern. A resonator comprising: two capacitor electrode patterns formed inside a substrate so as to face both the extended capacitor electrode pattern and the capacitor electrode pattern extended from the other coil pattern.