JPH0481887B2 - - 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.

2. Description of the Related Art Resonators used for filters, oscillation elements, etc. in the above frequency range have conventionally been dielectric coaxial resonators and ceramic resonators. A dielectric resonator has an equivalent circuit in which one capacitor and one coil are connected in parallel as shown in Figure 6A, while a ceramic resonator has an equivalent circuit in which one coil and one coil are connected in parallel as shown in Figure 6B. It has an equivalent circuit consisting of a series circuit of two capacitors and another capacitor connected in parallel.

Problems to be Solved by the Invention Since each resonator has only one coil in the equivalent circuit, it is not possible to magnetically couple multiple resonators using that coil. When configuring a filter by connecting resonators in multiple stages, there is a problem that separate parts such as a capacitor are required as a coupling means, resulting in a bulky structure.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide resonators that can be easily magnetically coupled to each other without using a separate coupling means.

Means for Solving the Problems In order to achieve the above object, the resonator of the present invention is an equivalent circuit in which two sets of LC series circuits each having coils connected in series on both sides of one capacitor are connected in parallel. The gist of the present invention is to have a circuit, and an embodiment in which the above object is achieved by means of this unique equivalent circuit will be described below.

Embodiment FIG. 1 is an equivalent circuit diagram of a resonator of the present invention,
It consists of two sets of LC series circuits A (B) connected in parallel, each having coils L1 and L2 (L3, L4) connected in series on both sides of one capacitor C1 (C2).

FIG. 2 shows an example of a resonator having the above equivalent circuit. Figure A is a front view, Figure B is a bottom view, and Figure C is a rear view. In the figure, 1 is a dielectric substrate made of FRDR material, etc., and capacitor electrode patterns 4, 5, 6, and 7 are formed on both ends of U-shaped coil patterns 2 and 3 on its front surface 1a and back surface 1b. A conductive pattern is formed, for example, by screen printing silver paste. Lead terminals 8 and 9 are connected to the bent portions of the coil patterns 2 and 3 by soldering or the like. Capacitor electrode patterns 4 and 7, 5 and 6 face each other with substrate 1 in between, and the dielectric constant and thickness of the substrate, electrode pattern 4
and 7, forming a capacitor with a capacitance determined by the opposing areas of 5 and 6. The capacitor formed by electrode patterns 4 and 7 corresponds to C1 in FIG. 1, and the capacitor formed by electrode patterns 5 and 6 corresponds to C2 in FIG. On the other hand, the coil patterns 2 and 3 form a coil in terms of high frequency. However, since the lead terminals 8 and 9 are connected to the middle of each coil pattern, each coil pattern forms two coils divided into two at the connection positions of the lead terminals 8 and 9. The coil formed by the coil pattern 2a between the lead terminal 8 and the capacitor electrode pattern 4 corresponds to L1 in FIG. The coil thus formed corresponds to L2 in FIG. Similarly, the coil formed by the coil pattern 3a between the lead terminal 9 and the capacitor electrode pattern 7 is L
3, lead terminal 9 and capacitor electrode pattern 6
The coil formed by the coil pattern 3b between the two corresponds to L4. The two coil patterns 2 and 3 have appropriate lengths to enable magnetic coupling with other resonators, and are preferably formed as close to both sides of the substrate as possible. Further, within the same resonator, it is desirable to space the two coil patterns 2 and 3 as far apart as possible so that they do not magnetically couple with each other or have capacitance. The illustrated example is implemented in the most distant state.

Next, specific dimensions of the above-mentioned resonator will be illustrated (unit: mm).

l1=6.9 l2=4.6 l3=5.5 l4=4.5 l5=4.0 l6=1.5 l7=1.7 Also, the dielectric constant ε of the substrate 1 is 75 and the thickness is 0.35 (mm)
It is. When setting the dimensions above, L1=L2=
6.5nH, L3=L4=3.5nH, C1=7pF, C2
= 51pF. The frequency characteristics of a resonator having this value are shown in FIG. The resonator's Q value was as high as 156. 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 is not found in conventional examples in terms of an equivalent circuit, and the width of the coil patterns 2 and 3 is Dielectric substrate 1
This is thought to be due to the use of FRDR material.

In the above resonator, the capacitor electrode patterns 4, 5, 6, 7 and the coil patterns 2, 3 are formed in the same pattern on both the front and back surfaces of the dielectric substrate 1. 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.

Further, in the above embodiment, the dielectric substrate 1 is
A 0.35mm thick one is used, but by changing the thickness, the capacitance of capacitors C1 and C2 changes and the resonant frequency can be changed, so choose an appropriate thickness in relation to the frequency of use. Good.

FIG. 4 shows another embodiment of the invention. In this embodiment, only two parallel coil patterns 12 and 13 are formed on the substrate 11, and a leaded capacitor 1 is formed across both coil patterns 12 and 13.
4 and 15 constitute a resonator. In this resonator, two coil patterns 12 and 13, a lead 14a of a capacitor 14,
The series line 14b corresponds to L1 and L2 in FIG. 1, and the leads 15a and 15b of the capacitor 15 correspond to L
3, corresponds to L4. C1 and C2 in FIG. 1 are constituted by external capacitors 14 and 15 in this embodiment. In this way, external capacitor 1
4 and 15, the substrate 11 does not need to be a dielectric, and in this example a printed circuit board is used.

In the resonator of this embodiment, the dimensions of the coil patterns 12, 13 and leads 15a, 15b to obtain the frequency characteristics shown in FIG. 2 are described below (units are
mm).

l11=6.0 l12=l13=5.5 l14=3.0 l15=1.5 FIG. 5 is a plan view showing a bandpass filter constructed using the above resonator. The resonator is A,
They are arranged in multiple stages as shown in B. Adjacent resonators A, B, and C can be connected to coil patterns 13a and 1 in close proximity to each other without using a separate coupling means.
2b, 13a, and 12c are connected by magnetic coupling. The degree of coupling is determined by factors such as the distance between two adjacent coil patterns and the length of each coil pattern (l11 in FIG. 3).

Effects of the Invention As explained above, according to the present invention, the resonator has a unique equivalent circuit in which two sets of LC series circuits in which coils are connected in series on both sides of a capacitor are connected in parallel. It is possible to provide a resonator with a high Q that is suitable for filters, oscillation elements, etc. used at frequencies above the band. Furthermore, since coils are connected in series on both sides of the capacitor, by using the coils, multiple resonators can be magnetically coupled without using a separate coupling means, forming a bandpass filter, etc. This has the remarkable effect of being very useful as a resonator for

[Brief explanation of the drawing]

Figure 1 is an equivalent circuit diagram of the resonator of the present invention, Figure 2 A is a front view of the resonator of an embodiment of the present invention, Figure 2 B is a side view of the resonator of Figure A, and Figure 2 H is a side view of the resonator of Figure A. 3 is a resonance characteristic diagram of the resonator, FIG. 4A is a plan view showing another embodiment of the present invention, FIG. 5B is a side view, and FIG. Figure 6 is a front view of an example of magnetic coupling using three resonators, and Figure 6 is a side view.
Figure A shows an equivalent circuit of a dielectric coaxial resonator, and Figure B shows an equivalent circuit of a ceramic resonator. A, B, C...Resonator, C1, C2... Capacitor, L1, L2... Coil, 1... Dielectric substrate, 2, 3, 12, 13... Coil pattern,
4, 5, 6, 7...Capacitor electrode pattern, 1
4,15... Capacitor.

Claims (1)

[Claims] 1. A resonator that has an equivalent circuit in which two sets of LC series circuits, in which coils are connected in series on both sides of a single capacitor, are connected in parallel.