JPS6180901A - Microwave filter using dielectric resonator - Google Patents

Abstract

PURPOSE:To manufacture easily a filter by providing plural center electric conductors in a dielectric of an integral construction, forming an electric conductor pattern on the end face of the dielectric by extending it from this center electric conductor, and adjusting this electric conductor pattern. CONSTITUTION:An electrical signal impressed from an input terminal 1 generates an electromagnetic field by a dielectric resonator 3 of an input stage provided in a dielectric of an integral construction, it is transmitted to a dielectric resonator 5 of the next stage through a coupling part 9 formed by an electric conductor pattern 14 and 16 extended from each center electric conductor and provided on the end face of the dielectric, and thereafter, it is transmitted to the next stage one after another in the same way. This electric conductor pattern can adjust not only an interstage coupling quantity but also a resonance frequency of each dielectric resonator 3-8. Also, these electric conductor patterns 14-19 can be adjusted by a mechanical method or an optical method, and also, since a dielectric of an integral construction is used, a filter having a desired characteristic can be manufactured easily.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to the structure of a microwave filter using a dielectric resonator.

(Prior Art) Conventionally, high frequency filters have been proposed in which a dielectric resonator, that is, a dielectric material having a high dielectric constant is used as a resonator.

A dielectric resonator has the advantage that a resonator can be realized with a size comparable to that of a strip line resonator, and an unloaded Q of the same magnitude as a waveguide resonator can be easily obtained.

In addition, the actual manufacturing process is either more complicated than that of a strip line resonator, or easier than that of a waveguide resonator.

However, dielectric resonators had the drawback of fatally poor temperature characteristics, but advances in dielectric material engineering are beginning to solve this problem. Therefore, dielectric filters using dielectric resonators are extremely important. For these reasons, filters using dielectric resonators are expected to be used more and more in the future.

As such filters using dielectric resonators, filters disclosed in Japanese Patent Application Laid-open No. 54-3448, Japanese Patent Application Laid-Open No. 55-68702, and Japanese Patent Laid-Open No. 56-144602 have been proposed by the applicant of the present application. .

FIG. 2 shows an example of the configuration of a conventional microwave filter using a dielectric resonator. Input/output terminals 21, 22 provided at both ends of the metal case and transmission lines 23, 24 connected to them are arranged, and between the transmission lines 23, 24, six core-shaped or prismatic dielectrics are separated. resonator 25,
26, 27.

28 are arranged on a single side of the metal case.

To configure the filter, input and output transmission lines 23°24
and the dielectric resonators 25 and 28 are set to a desired magnitude. This coupling is set by changing the distance d between the resonator 25.28 and the transmission line 23.24. That is, if the spacing d is narrowed, the coupling becomes tighter, and if the spacing d is widened, the coupling becomes smaller. Also, dielectric resonator 2
The intervals of 5.26°, 27.28°, and 27.28° must also be selected so that the degree of coupling necessary for realizing the filter can be obtained.

The principle of this operation will be briefly explained. FIG. 3 is a diagram showing the relationship between current and magnetic field, and 31 is a conductor.

According to electromagnetism, when electric current flows through a conductor, an electromagnetic field is generated. The magnitude of the electromagnetic field generated by this current decreases as the distance from the conductor increases.

Since the dielectric resonator and the transmission line are coupled together via an electromagnetic field, the amount of coupling can be changed by changing the distance between the dielectric resonator and the transmission line. This is the second
This is the reason why in the conventional filter shown in the figure, the amount of coupling increases as the spacing decreases.

Claims (1)

[Claims] A microwave filter using a plurality of dielectric resonators formed in a homogeneous single dielectric material, provided with a coupling pattern on the center conductor, and filled with the dielectric material between the center conductors.