JPH011303A - high frequency filter - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is used in various high frequency devices and equipment, and is applicable to UHFH.
This invention relates to a high frequency filter using a ring resonator in the frequency band above F.

2. Description of the Related Art It is known that a split ring resonator having a structure in which two transmission lines are arranged in a loop and both ends thereof are connected by capacitance exhibits good characteristics in the upper frequency band of the UK band.

Regarding the filter using this resonator, Patent No. 1348
No. 722 or No. 1007337 describes an electronically tuned filter using a suspended strip line, and FIG. 4 shows an example of a three-stage bandpass filter (B PF ) with a fixed center frequency.

In FIG. 4, 11; 12, 13 are split ring resonators having frequency tuning capacitances 11a to 13a;
4.15 is an input/output coupling capacitance, and 41.42 is an input and output terminal. As can be seen from FIG. 4, the split ring resonators 11 to 13 do not require high-frequency grounding, and furthermore, the coupling between the resonators 11 to 13 can be easily realized by parallel coupling. When applied to a filter, the structure is extremely simple and the characteristics are good.

Problems to be Solved by the Invention As described above, filters using split ring resonators have good characteristics, but have the disadvantage of being large in size.

In view of the recent demand for downsizing of devices, the present invention aims to downsize devices using split ring resonators without impairing their good characteristics.

Means for Solving the Problems The present invention provides two ring resonators each having an 8-inch ring connected to both open ends of a loop-shaped transmission line so as to be coupled to each other, and an input or output terminal connected to the loop-shaped resonator. The above object is achieved by providing the device inside the transmission line of the device.

For production The operation of the present invention with the above configuration is as follows.

That is, since a strip line is used as the transmission line of the split ring resonator, the thickness of the circuit or device such as a filter is not required to be very large, so it is necessary to reduce the area of the circuit for miniaturization. Therefore,
The present invention aims to downsize the circuit by providing the input/output circuit in the portion surrounded by the ring or loop of the resonator.

Example An embodiment of the present invention will be described below.

FIG. 1 is a plan view of a high frequency filter (three-stage BPF) in a first embodiment of the present invention. In Figure 1, 1
1.12.13 is the capacity for frequency tuning 5) 11 a~1
A split ring resonator 3a, 14, 15 are capacitors for input/output coupling, and 16 and 17 are input and output terminals, specifically coaxial connectors or pin terminals.

As described above, by providing the input and output terminals approximately at the center inside the loops of the split ring resonators 11 to 13, it is possible to reduce the size of the combined housing.

FIG. 2 is a plan view of a high frequency filter in a second embodiment of the invention. The difference in FIG. 2 from the first embodiment shown in FIG. 1 is that the coupling capacitors 14, 15 used for input/output in FIG. 1 are replaced with magnetic coupling loops 21, 22. This coupling loop 21.22 also connects the resonator 11.
Similarly to the first embodiment, the input/output terminals 16 and 17 can be arranged inside the ring resonator 11-13 at the center portion of the inner path of the ring resonator 11-13.

In the above first and second embodiments, the number of BPF stages is three, and the shape of the ring resonator is a square loop, but the number of stages may be any number, and the shape of the loop may also be circular,
It goes without saying that a rectangular shape is also good.

Next, a third embodiment of the present invention will be described.

FIGS. 3(A) and 3(B) are a plan view and a side sectional view of a ring resonator which is a main part of a high frequency filter in a third embodiment of the present invention.

In FIG. 3, 31 is a dielectric split ring resonator, 32 is a coaxial connector, 33 is a center conductor of the coaxial connector 32, and 34 is a metal conductor for mounting the coaxial connector 32 (which becomes the conductor of the device).

According to the above configuration, the ring resonator 31 has the function of a notch filter, but since it is possible to adopt a structure coaxially integrated with the coaxial connector 32, the ring resonator 31 has a function of a notch filter.
Can be made smaller.

Effects of the Invention As described above, the present invention provides ring resonators formed by connecting capacitors to both open ends of a loop-shaped transmission line, arranged so as to be coupled to each other, and connecting input or output terminals to the loop-shaped resonator. By providing the ring resonator inside the transmission line of the device, the filter using the ring resonator can be made compact with a simple configuration, and its industrial value is extremely large.

[Brief explanation of the drawing]

1 and 2 are plan views of high frequency filters in the first and second embodiments of the present invention, and FIGS. 3(A) and 3(B) are plan views of high frequency filters in the third embodiment of the present invention (; Fig. 4 is a plan view and a side sectional view of a ring resonator which is the main part, and Fig. 4 is a plan view of a conventional high frequency filter.11-13...Ring resonator, 14.15...Capacitor, 16. 17... Input/output terminal, 21, 22...
・Magnetic field coupling loop. Name of agent: Patent attorney Toshio Nakao (1st person)
Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] Another feature is that ring resonators formed by connecting capacitors to both open ends of a loop-shaped transmission line are arranged so as to be coupled to each other, and an input or output terminal is provided inside the transmission line of the loop-shaped resonator. high frequency filter.