JPS61219201A - Dielectric resonance type band stopping filter - Google Patents

Abstract

PURPOSE:To use a metallic chassis and metallic cover which are relatively small in dimension and the same in a certain wavelength zone, by making a conductor pattern formed on a dielectric substrate to make a detour between dielectric resonators. CONSTITUTION:It can be said from a filter theory that, when the electric length, namely, conductor pattern (l) between dielectric resonators is l=l1+l2+l3+l4+l5=(2n-1)X(lambdag/4), the characteristic of a filter becomes the optimum. Therefore, the length L1 can be made smaller as compared with conventional ones at the same frequency and, as a result, the length L of a metallic chassis can be made smaller as compared with conventional ones. Moreover, if the l2 and l4 are appropriately selected when a frequency is fixed, the length L1 can be selected with a considerable degree of freedom. In addition, when this constitution is used, the length L1 can be made constant by selecting suitable values for the detouring widths l2a-l2c of the detouring path of a conductor pattern in a range of l2b>l2a>l2c, so that the electric length between dielectric resonators can become (2n-1)X(lambdag/4) against each of frequencies f2, f1, and f3. Accordingly, the distance L between dielectric resonators also becomes constant and the outer shape of the metallic chassis becomes a fixedly designed one.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a dielectric resonant band-elimination filter constituted by a plurality of dielectric resonators.

〔overview〕

The present invention reduces the external dimensions of a dielectric filter that utilizes a distributed constant generated in a conductor pattern by making the conductor pattern on the dielectric substrate detoured.

[Conventional technology]

FIG. 4 shows an example of the configuration of a conventional dielectric resonance type band-elimination filter. FIG. 4 shows an example of a two-stage dielectric resonance type band-elimination filter, in which (a) shows a plan view with the metal cover removed, and (a) a side cross-sectional view. In this figure, 1.2 is a dielectric resonator, 3.4 is its support, 5 is a metal chassis, 6 is a metal cover, 7.8 is a frequency adjustment screw,
Reference numeral 9 is a dielectric substrate, reference numeral 10 is a conductive pattern formed on the dielectric substrate 9, and reference numerals 11 and 12 are input and output connectors, respectively.

In the conventional configuration example shown in FIG. 4, the conductor pattern IO is linear. On the other hand, the distance between the dielectric resonators, /, is determined as (2n-1)X(λg/4) based on the filter design logic. Here, λg is one wavelength on the dielectric substrate, and n is a positive integer of 1 or more (1, 2, 3, ...)
It is.

In this way, in the conventional configuration, the center distance L, / between the two dielectric resonators is uniquely determined by L+' = (2n 1)X (λg/4), but L1' is a function of λg. Therefore, when the frequency changes, the above L and P change.

For example, when using this device as a wireless communication device, even within one radio frequency band, for example, the frequency range is 3.6 to 4.2 GHz for the 4 GHz band, and 5.9 to 6 GHz for the 6 GHz band. If the frequency is different, such as the .4 GHz band, the lengths of L and l will also be different.

[Problem that the invention seeks to solve]

However, since the conductor pattern is on a straight line, /
If the length of the metal chassis changes, the length L' of the metal chassis must also be changed. As a result, the dimensions of this device may be large, and there is also the drawback that a metal chassis and metal cover must be designed for each type of dielectric substrate.

SUMMARY OF THE INVENTION An object of the present invention is to provide a dielectric resonant band-elimination filter whose dimensions are relatively small and in which the same metal chassis and metal cover can be used within a certain wavelength range.

Means for Solving Problem C] In order to solve the conventional drawbacks, the present invention is characterized by using a configuration in which a conductive pattern formed on a dielectric substrate is detoured between dielectric resonators. There is.

That is, the present invention includes a metal chassis, a dielectric substrate included in the metal chassis, and a conductor pattern formed on the surface of the dielectric substrate, and the conductor pattern is controlled by a distributed constant generated in the conductor pattern. In a dielectric resonant band-elimination filter having a structure that gives a desired frequency characteristic to an electrical signal passing therethrough, the above-mentioned conductor pattern is partially formed in a detour shape so that the electrical length is longer than the actual length. Features.

It is desirable that the metal chassis have the same shape for filters with different frequency characteristics.

[For production]

The straight line distance between two fixed points on a plane is constant, but
By detouring the route connecting these two points and following this route, the distance between the two points can be set to any value.

By detouring the conductor pattern connecting the dielectric resonators on the dielectric substrate and changing the crossing distance, even if the position of the dielectric resonator is fixed, the conductor pattern corresponding to the different frequencies flowing through the circuit can be created. A dielectric resonant bandpass filter having a pattern length is constructed.

〔Example〕

An embodiment of the present invention will be described with reference to the drawings.

FIG. 1(a) shows a plan view of the interior of the above embodiment;
Figure (b) also shows a side sectional view. Note that elements having the same functions as those in FIG. 4 are given the same reference numerals.

According to filter theory, the length of the conductor pattern on the dielectric substrate between the dielectric resonators is (2n-1)X (λg/4). In this embodiment, this length is realized by the shape of the conductor pattern that is detoured, as shown in FIG. 1 [al].

In this figure, the electrical length between dielectric resonators, that is, the length i of the conductor pattern, is ! =j! , +72. +j! , +1. , +1%
According to filter theory, 1, +4□+12. +14+! .

=(2n-1)X(λg/4), the filter characteristics are optimal. Therefore, by using the present invention, the first
LI in the figure can be made smaller than L' in the conventional configuration example of FIG. 4. Therefore, the outer shape of the metal chassis in the first diagram of the present invention can be made smaller than L' in the conventional example in FIG. 3. Also, when the frequency is determined, in the conventional example, L
, l are uniquely determined by (2n-1)X(λg/4), whereas in this example, by appropriately selecting 12.14, it is possible to select with a considerable degree of freedom. can.

Furthermore, as shown in FIG. 2, by partially changing the shape of the conductor pattern, a dielectric resonant band-elimination filter with optimal characteristics can be constructed using a metal chassis with the same external dimensions even when the frequency changes.

In Figure 2, the frequency f is f2<f, <f.

FIG. 3 is a comparison diagram of the length of a conductor pattern for three waves. In the conventional configuration example, when the frequency changes, L and I change, so the external dimension L' also changes, but with the configuration of the present invention, the frequencies f2, f, , f,
As shown in (al, (b) and (e) in Figure 2, conductors are Pattern detour width 12l1t
By selecting appropriate values for b and 12c such that βZb>1za>IZc, Ll can be kept constant. Therefore, the distance between the dielectric resonators is also constant, and the outer shape of the metal chassis is designed to be constant.

Therefore, according to the present invention, it is possible to design a metal chassis whose external dimensions are smaller than those of the conventional structure at the same frequency, and whose external dimensions are constant within a certain frequency change range.

Next, a comparison between the present invention and a conventional example will be explained using FIG. A design example of a dielectric resonant band-elimination filter used in the 4 GHz band of wireless communication equipment is shown below. In the 4Gllz band, 3.6 to 4.2 GHz is normally used.

Now, if we assume three waves with frequencies of 3.6 GHz, 3, 9 GHz, and 4.2 GHz, the electrical length between the two dielectric resonators is 43.4 GHz, respectively, according to filter theory.
7 cranes, 40.13 am and 37.32 am.

Therefore, in the conventional configuration shown in FIG. 3(a), each value of KI must be set to this length. Also, the standard dimension from the center of the dielectric resonator to the end face of the metal chassis is usually 2 (ha), so the total length of the metal chassis is 83.47 m, 80.13 m, and 77 m, respectively.
It becomes the 321st seal.

However, according to the present invention, as shown in FIG. 3(b), the length is fixed at 30 m and the conductor pattern is detoured. That is, by biasing the central portion of the conductive pattern as shown in the figure, it is possible to obtain the respective predetermined electrical lengths determined from the filter theory. Therefore, the length k of the metal chassis is a constant value of 70 m.

The above relationships are shown in a table and compared.

Table [Effects of the Invention] As explained above, according to the present invention, by making the conductor pattern between the dielectric resonators detoured, the electrical length between the dielectric resonators exhibiting optimum characteristics can be shortened. The chassis becomes smaller. In addition, since the overall length of the chassis can be made constant for different frequencies within a certain range, the design of dielectric resonant bandpass filters and the equipment to install them are both simplified, reducing manufacturing and construction costs. It has the effect of

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention, and (a) is an internal plan view;
(b) is a side sectional view. FIG. 2 is a comparison diagram of conductor patterns optimal for different frequencies according to the present invention. FIG. 3 is a comparative explanatory diagram for the same electrical length between the conventional example and the embodiment. Figure 4 is a configuration diagram of a conventional example, (a) is an internal plan view, (b)
l is a side sectional view. 1.2... Dielectric resonator, 3.4... Support stand, 5...
...Metal chassis, 6...Metal cover, 7.8...
Frequency adjustment, 9... Dielectric substrate, 10... Conductor pattern, 11... Input connector, 12... Output connector.

Claims (2)

[Claims] (1) Includes a metal chassis, a dielectric substrate included in this metal chassis, and a conductor pattern formed on the surface of this dielectric substrate, and electricity that passes through this conductor pattern due to a distributed constant generated in this conductor pattern. In a dielectric resonant band-elimination filter having a structure that gives a signal a desired frequency characteristic, the conductor pattern is characterized in that a part of the conductor pattern is formed in a detour shape so that the electrical length is longer than the actual length. Dielectric resonant band-stop filter. (2) The dielectric resonant band-elimination filter according to claim (1), wherein the metal chassis has the same shape for filters with different frequency characteristics.