DE2340492A1 - Adjustable multi-section waveguide filter of square cross-section - uses direction of indentations in prefabricated side plates for coarse frequency adjustment - Google Patents

Abstract

The microwave filter consists of one or more waveguide filter sections of rectangular cross-section constructed of interlocking prefabricated metal plates forming the sidewalls, endface cups and partitions which are finally soldered together. At least one of the sidewalls has a bowl shaped indentation which can be directed into the interior of the waveguide or which can be going outward depending on the frequency range of the filter. All sidewalls have identical indentations but can have different cut-outs and attachments. Each partition wall having a coupling hole can with its lugs mate with the appropriate slots in the appropriate slots in the sidewall plates. The so formed individual cavity resonators can be fine adjusted by means of a dielectric plungers fixed to a metal screw in the sidewall. An additional coupling hole in the partition close to the sidewall can be used to alter the coupling by means of a screw. The frequency range is coarse-adjusted by the choice of the number of inward and outward directed indentations.

Description

Licentia Patent-Verwaltungs-GmbH PT-BK / Thn / jo

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Multi-circle waveguide filter with a rectangular cross-section

The present invention is concerned with a microwave filter, consisting of a multicircular waveguide filter with a rectangular cross-section, which is assembled and soldered from prefabricated metal sheets, such as side walls, end plates and panels as partition walls.

Multi-circuit waveguide filters, in which the individual resonance circuits are arranged one behind the other, are in the maximum frequency technology widespread and are used in a wide variety of designs

Couplings are arranged between the individual circles, which can be selected capacitively or inductively and as breakthroughs or else Loops are carried out.

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To adjust the filter or the individual circles, stamps are used that can be changed by means of screws and inserted into the Immerse the cavity of each individual resonance circuit.

This type of filter has various disadvantages, which consist in the fact that the frequency range that can be covered is limited by means of the tuning stamp, i.e. if you want to go beyond the intended frequency range, the dimensions of the filter must be recalculated and designed. On the other hand, the bandwidth of the filter changes with the depth of immersion of the tuning temple, a disadvantage that only changes with special effort can be overcome.

This results in the object on which the invention is based. It consists in creating a filter that can be easily installed with a minimum of tools.

en. gen and by appropriate modification for a large one

Frequency range is usable or composable.

According to the invention, this object is achieved by the in claim 1 specified invention solved. The basic concept of the invention specified in claim 1 is expanded and described in the remaining subclaims.

With this invention it has been possible to create a waveguide filter that has a wide frequency range in its con-

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Reception can be assembled and manufactured from unit parts is. This not only results in a substantial reduction in the price, but also shows the way in which a uniform construction method can be achieved in this area.

The concept of the invention is explained in more detail in some exemplary embodiments with reference to the drawing. Show in detail:

Fig. 1 shows a multi-circle waveguide filter in a perspective view partly shown in section, Fig. 2 different embodiments for different

Frequency ranges and 3a shows the top view,

b the front view and

c the view from below of a further embodiment of filters according to the invention.

In Fig. 1, a multi-circuit filter 1 is shown. It consists of the resonance circuits la, Ib and lc, which are separated from one another by diaphragms 2 with coupling openings 2a. End plates 3 ^{on the} front and back are each provided with a connector 3 a, which serve as an input or output of the filter. The individual resonance circuits la, Ib and Ic are provided with tuning stamps 4 and consist of a threaded screw part 4a and the actual tuning element 4b made of a dielectric material that protrudes into the cavity of the respective resonance circuit.

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The diaphragms 2 are provided with pins 2b, which when assembled of the filter through slots milled into the side walls A, B, C and D. The side walls A, B, C and D are alternately provided with recesses and projections A ", B", C "and D" and become alternate when they are put together arranged opposite one another (B ", C" Fig. 1).

The coupling openings 2a, in this embodiment as Executed bores, are arranged eccentrically, namely on the side facing away from the tuning die 4, in order to influence to keep the coupling as small as possible by immersing the tuning die 4 in the resonance chamber.

The coupling of the individual resonance circuits la, Ib and ic with one another takes place by means of the coupling openings 2a. These openings are designed in their width so that this coupling is too small in its electrical effect. It is therefore necessary to provide an additional coupling that also is incorporated into the panels. It consists of one on a side wall, preferably the side wall, which is the tuning die 4 is opposite, and consists of a rectangular opening 2b which is adjacent to the side wall D. the Side wall D is provided at this point with a threaded hole 2d into which a screw for adjustment the coupling can be screwed. This breakthrough 2b is now designed in its dimensioning so that by means of the screw

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be the required coupling can be set.

The side walls A, B, C, D of the filter 1 have bead-shaped bulges A ¹ , B ¹ , C ¹ , D ¹ , which optionally, depending on the desired frequency range, protrude into the waveguide space, as in C, or which are also directed outwards are, as with A ¹ , B 'and D ¹ . In FIG. 3b , the arrangement of the side walls A, B, C and D is implemented in such a way that their bead-like curvatures protrude outwards. Further embodiments are shown in FIGS. 2a, 2b and 2c. In Fig. 2a, three side walls B, C and D are directed outwards and the side wall A with its curvature A ¹ inwards into the waveguide. This embodiment is designed for a higher frequency range than the embodiment of FIG. 3.

Fig. 2b is designed for the next higher frequency range, with two side walls A and D to the inside and B and C are directed outwards. In FIG. 2c, one side wall B is to the outside and three side walls A, C and O directed inwards. The highest possible frequency range can be realized with an embodiment, in which all four side walls A, B, C, D are curved inwards (not shown).

The filter 1 shown in Fig. 1 is only a

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Embodiment. The number of resonance circles is by no means limited to three, but the idea of the invention includes a single resonance circuit just like that Number η includes any number of resonance circles. It is irrelevant whether the frequency range by bead-shaped or cup-shaped formations in the side walls is determined.

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Claims (6)

Patent claims ψΐ * j Microwave filter, consisting of a multicircular waveguide filter with a rectangular cross-section, which is assembled and soldered from prefabricated sheets such as side walls, cover sheets and panels as partition walls, characterized in that at least one side wall (A, B, C, D) of the filter (l) has at least one cup-shaped or sink-shaped curvature (Α ', Β', ΟΌ ¹ ), which either protrudes into the waveguide space or is directed outwards, depending on the frequency range. 2. Microwave filter according to claim 1, characterized in that the side walls (A, B, C, D) are arranged alternately with recesses (A ¹¹ , B ", C", D ") and approaches lying opposite one another« 3. Microwave filter according to claim 1, characterized in that _{diaphragms provided with coupling openings (2a) are arranged as partition walls (2) between the resonance circuits (la, Ib 1} ic), which are inserted with their pins (2c) into slots in the side walls (A, B, C, D) intervene. 4.x microwave filter according to claim 3 »characterized in that that the coupling openings are perforations (2a) arranged off-center. ^{BK 73/4} 509808/0615 5. Microwave filter according to claim 4, characterized in that the circles (-la, Ib, Ic) of the filter with a dielectric Existing material and stamps (4b) used in metal screws (4a) can be finely adjusted, with the coupling openings (2a) in the aperture (2) on the Stamp (4b) facing away from the sides are arranged. 6. Microwave filter according to claim 3, characterized in that that a further coupling opening (2b) is arranged on at least one side wall (A, B, C, D) and the coupling by means of one through the side wall (A, B, C, D) into the other Coupling opening (2b) protruding, changeable screw is variable. BK 73/4 509808/061 5 Blank page