JPS6162203A - Microwave filter using dielectric resonator - Google Patents

Abstract

PURPOSE:To attain low cost and case of assembling of a dielectric resonator by coupling a resonator formed continuously incorporatedly with a dielectric having a slot among plural columnar dielectric resonators and constituting partly said resonators by means of plural spatial couplings. CONSTITUTION:The dielectric resonators 3, 4 and 5, 6 are formed as one block each, and the one block resonator is formed by an incorporated dielectric and slot couplings 7, 8 are formed among the resonators. Then the spatial coupling 9 is provided among the resonators of each block. Thus, an electromagnetic field is generated from an input signal by the dielectric resonator 3 and this electromagnetic field is propagated to the inter-stage resonator 4 via the coupling 7 and to the inter-stage resonator 5 via the spatial coupling 9. Further, the resonance frequency is decided by the height of the dielectric resonator (height of an inner conductor 10) and the frequency adjusting pattern 11 and it is possible to make this adjustment by mechanical or optical processing method.

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

In addition, the actual manufacturing process is more complicated than that of a stripline resonator, but it is 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 1 and 2 provided at both ends of the metal case and transmission line 2 connected to them
3.24 is arranged between the transmission lines 23 and 24, and dielectric resonators 25 and 26 each having a core shape or a prismatic shape are separated.
, 27.28 are arranged. The coupling between the input/output transmission lines 23, 24 and the dielectric resonators 25.degree. 28 constituting the filter is set to a desired magnitude. This coupling setup consists of a resonator 25.28 and a transmission line 2,'l.

This is done by changing the distance d from 24.

That is, if the spacing d is narrowed, the coupling becomes tighter, and if the spacing d is widened, the coupling becomes smaller. Dielectric resonator 25
．． Second, the intervals between 27 and 28 must be selected such that the required degree of coupling is 1:1 when realizing the filter.

The principle of this operation will be briefly explained. FIG. 3 is a diagram showing the relationship between current and magnetic field, and 29 is a conductor.

According to electromagnetism, when electric current flows through a conductor, an electromagnetic field is generated. The electric current generated by this current (magnetic field size 1/i
It decreases as the distance from the four increases.

Since the dielectric resonator and the transmission line are coupled through 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.

In addition, the present applicant has filed an application as JP-A No. 57-48801 in which grooves or holes are provided between inner core bodies in a plate-shaped dielectric material without manufacturing each dielectric resonator individually. There is.

(Problems to be solved by the invention) In this way, conventional filters realize dielectric filters by cascading individual core-shaped or prismatic single resonators. A) to address the shortcomings.

(1) When assembling each dielectric resonator, it is difficult to precisely arrange the distance from the center of the resonator, that is, the pitch between the inner conductors, and the characteristics tend to fluctuate.

(2) Since each dielectric resonator exists independently, it is difficult to fix the dielectric resonators necessary to construct the filter.

(3) When realizing steep characteristics, many dielectric resonators are required, but in this case, each dielectric resonator is added.
), the unit cost of the dielectric resonator becomes expensive due to the
The price of the filter will also be high.

Furthermore, in the case where grooves or holes are provided between the inner conductors of a plurality of resonators, the filter is made of a single dielectric material, so there is a drawback that the yield rate of the dielectric filter cannot be increased.

(Means for Solving the Problems) The filter of the present invention includes a plurality of dielectric resonators in one block, and the dielectric resonators in one block are formed of a single dielectric. The individual resonators within the integral dielectric are columnar, so grooves are formed between the individual resonators, and since the dielectric is integral, a portion of the resonators are continuously formed between the individual resonators. It is.

The resonators of each Glock forming a plurality of dielectric resonators are completely separated by space and connected multiple times through spatial coupling.

(Function) The applied electric signal generates an electromagnetic field by the dielectric resonator of the input stage, and this electromagnetic field causes coupling between the grooves formed between adjacent interstage dielectric resonators in the same dielectric. The electromagnetic field is transmitted to the adjacent interstage resonator through the section. The electromagnetic field that has reached the groin resonator 4 is transmitted to the second groove through a spatial coupling section provided between the first groove formed by the dielectric and the second groove formed by another dielectric block. It is transmitted to the interstage resonator formed in the groove. The electric signal is transmitted to the final stage dielectric resonator by repeating this operation one after another.

It is estimated that the coupling between each dielectric resonator is caused by inhomogeneity between electric field coupling and magnetic field coupling.

(Embodiment) FIG. 1 is a perspective view for explaining a birch construction according to an embodiment of the present invention, and a metal case covering the entire structure is omitted. 1st
In the figure, 1 is an input terminal, 2 is an output terminal, 3 is an input stage dielectric resonator, 4 and 5 are dielectric resonators between the legs, and 6 is an output stage dielectric resonator.

7.8 is a t117 coupling portion, and 9 is a spatial coupling portion that couples the first dielectric block and the second dielectric block.

10 is an inner conductor, and 11 is a turn connected to the inner conductor 10.

The operation of this microwave filter is such that an electric signal applied from the input terminal generates an electromagnetic field due to the dielectric resonances 2:'r and 7 of the manual stage provided in the first dielectric group. The electromagnetic field is transmitted to the interstage resonators 4 via grooved coupling portions 7 provided between adjacent interstage resonators 4. The electromagnetic field that has reached the interstage resonator 4 is transmitted to the interstage resonator 5 formed in the dielectric block 2 via the spatial coupling section 9 provided between the dielectric block 1 and the dielectric Glock 2. tell. While repeating such operations one after another, an electric signal is supplied to a load provided at the output of the dielectric filter.

Next, the resonant frequency of each dielectric resonator provided here is determined by the height of the dielectric resonator (the height of the inner conductor 1o) and the frequency 1
! It is determined by the adjustment, turn 11, etc., and this adjustment can be performed by a mechanical method or an optical method.

The joint part is the width of the groove provided in the dielectric block.

Determined by the depth etc., the coupling between the dielectric grooves and grooves is determined by the depth etc.
It can be determined by the spacing between the y-rings, and the length is adjusted to obtain the degree of coupling necessary to construct the filter.

(Effects of the Invention) As explained above, this invention realizes a dielectric resonator by providing a plurality of cylindrical center conductors using a dielectric material, and constructs a filter using these dielectric resonators. for,
The distance between these dielectric resonators is determined by the dimensions of the grooves necessary to obtain the degree of coupling necessary to realize the filter. Further, the spacing between each dielectric block is adjusted to a length that provides the degree of coupling necessary to construct the filter.

Therefore, in the dielectric filter of this invention, a dielectric resonator is realized by providing a cylindrical center conductor in a dielectric block, and a microwave filter is realized by combining blocks with a structure in which grooves are provided between the resonators to obtain coupling. This allows flexibility in the size of the dielectric material, and the distance between the center conductors, which has the largest characteristic variation in this type of filter configuration, does not vary much during assembly. This method has advantages such as easy installation because the dielectric 5 (i) is integrated.

Further, the feature of this dielectric filter is that the dielectric filter is divided into several groups a2 of dielectric resonators.

This reduces the number of times to precisely set the spacing between the cylindrical center conductors of the dielectric resonator, and improves the yield of dielectric filters.

[Brief explanation of the drawing]

FIG. 1 is a perspective view for explaining an embodiment of the present invention, FIG. 2 is a plan view of a conventional dielectric filter, and FIG. 8g3 is a diagram showing the relationship between current and magnetic field. 3.4, 5.6... Dielectric resonator, 7, 8... Groove coupling portion, 9... Spatial connection-end portion. Patent applicant: Oki Electric Industry Co., Ltd. Figure 1 Figure 2

Claims (1)

[Claims] A plurality of columnar dielectric resonators each having a groove between them and a part of which is continuously formed integrally with a dielectric constituting the dielectric resonator are connected by spatial coupling. A microwave filter using a dielectric resonator.