CN115764209A - A design method of circular waveguide dual-mode filter with TE01 and TM11 - Google Patents

Abstract

A design method of a TE01 and TM11 circular waveguide dual-mode filter comprises two hollow circular cavities, an input coupling stop waveguide, an output coupling stop waveguide, a cavity and a cover plate, wherein the two hollow circular cavities are respectively connected with the input coupling stop waveguide and the output coupling stop waveguide, the coupling stop waveguide is connected with the two hollow circular cavities, the cavity is provided with a groove, the two hollow circular cavities, the input coupling stop waveguide, the output coupling stop waveguide and the coupling stop waveguide are correspondingly connected in shape and size and are used for being embedded, and the cover plate is fixed on the cavity through screws to form sealing.

Description

A design method of circular waveguide dual-mode filter with TE01 and TM11

technical field

The invention belongs to the field of microwave technology, and in particular relates to a filter technology.

Background technique

In the fields of communication satellites and aerospace, cavity filters are very important passive components, such as TE102, TE201, TE301 rectangular waveguide dual-mode, and traditional TE11p circular waveguide dual-mode.

TE102 and TE201 rectangular waveguide dual-mode filters can’t arrange the cavities on a straight line. Although TE01 solves the problem that the cavities cannot be aligned on a straight line, the input coupling cut-off waveguide and output coupling cut-off waveguide are too thin to be processed in engineering, and The dual mode is large in size.

The TE11p circular waveguide dual-mode filter can only achieve symmetrical transmission zero point, the input-output coupling diaphragm and the coupling diaphragm in the middle are too thin, and the cross holes on the diaphragm need wire cutting, which makes the processing complicated. The entire filter needs to be processed in sections, and many fastening screws are required for assembly, resulting in low assembly accuracy. Screws cannot be added to the diaphragm, time-consuming debugging and poor waveform.

Contents of the invention

In order to solve the problems existing in the prior art, the present invention proposes a design method for circular waveguide dual-mode filters of TE01 and TM11. In order to achieve the above purpose, the present invention adopts the following technical solutions.

The filter consists of two hollow cavities, an input coupling cut-off waveguide, an output coupling cut-off waveguide, a coupling cut-off waveguide, a cavity, and a cover plate. The two hollow cavities are respectively connected to the input coupling cut-off waveguide and the output coupling cut-off waveguide , the coupling cut-off waveguide connects two hollow circular cavities, the cavity is provided with a groove, the shape and size correspond to the connected two hollow circular cavities, the input coupling cut-off waveguide, the output coupling cut-off waveguide, the coupling cut-off waveguide for their embedding, and the cover plate It is fixed on the cavity by screws to form a seal.

The diameters of the two hollow cavities are respectively changed to realize simultaneous resonance of the two modes of TE01 and TM11 at the required center frequency.

Change the aspect ratio of the two hollow circular cavities respectively, change the circular cavity into an elliptical cavity, form a perturbation, separate the two modes of TE01 and TM11, generate a coupling relationship, and form the coupling bandwidth required by the filter design, so that the two The non-resonant modes of the hollow circular cavity create transmission zeros.

The width and length of the input-coupling cut-off waveguide and the output-coupling cut-off waveguide, as well as the positions deviated from the centers of the two hollow cavities are adjusted to meet the input bandwidth and output bandwidth required by filter design.

The width and length of the coupling cut-off waveguide connecting the two hollow cavities and the positions deviated from the centers of the two hollow cavities are adjusted to meet the coupling bandwidth required by the filter design.

In the overall modeling and simulation of the three-dimensional electromagnetic field simulation software HFSS or CST, repeat the above steps several times until the filter bandwidth, out-of-band suppression and return loss meet the design requirements.

Beneficial effects of the present invention:

The filter has high power, high Q value, low loss, and the position of transmission zero point can be freely controlled. It is suitable for large-scale production, can be applied to practical engineering, and meets the increasing application requirements of communication systems at this stage.

Because the Z-axis direction of the TE01 and TM11 circular waveguide dual-mode filters is not limited, by increasing the height of the circular waveguide in the Z-axis direction, it is possible to increase the unloaded quality factor Q value of the cavity, reduce the insertion loss of the filter, and filter The internal mode of the device will not be changed by this.

TE102 and TE301 rectangular waveguide dual-mode filter cavity can overcome the problem that the cavity discharge of TE102 and TE201 rectangular waveguide dual-mode filter is not in a straight line, and can be integrated on the CNC milling machine to reduce assembly errors. If the machining accuracy is controlled within a certain range , It can realize the link of free debugging and large-scale production.

TE01 and TM11 circular waveguide dual-mode filters are a new type of dual-mode filter, which can control the position of the transmission zero point by changing the ratio of the diameter of the circle. It is suitable for cavity filters in the fields of communication satellites and aerospace, and is currently used in international and domestic applications. Has outstanding advantages.

Description of drawings

Figure 1 is a disassembled structure diagram, and Figure 2 is a simulation waveform diagram.

Reference numerals: 1 - cavity, 2 - coupling cut-off waveguide, 3 - input coupling cut-off waveguide, 4 and 5 - hollow circular cavity, 6 - output coupling cut-off waveguide, 7 - cover plate.

Detailed ways

The technical solution of the present invention will be specifically described below in conjunction with the accompanying drawings.

The structure of the filter is shown in Figure 1, the hollow circular cavity 4 is connected to the input coupling cut-off waveguide 3, the hollow circular cavity 5 is connected to the output coupling cut-off waveguide 6, the coupling cut-off waveguide 2 is connected to two hollow circular cavities 4 and 5, and the cavity 1 is set The shape and size of the groove correspond to the connected hollow cavities 4 and 5, the input coupling cut-off waveguide 3, the output coupling cut-off waveguide 6, and the coupling cut-off waveguide 2 for their embedding. The cover plate 7 is fixed on the cavity by screws to form a seal.

The installed filter is equivalent to a fourth-order generalized Chebyshev filter with a pair of transmission zeros, and the synthesis of its coupling matrix is the same as that of a typical generalized Chebyshev filter. The simulation waveform is shown in Figure 2, and the HFSS simulation filter The center frequency of the device is 14.977GHz, the bandwidth is 112MHz, the out-of-band rejection is 14.613GHz, the rejection is greater than 60dB, and the return loss is greater than 19dB.

The above as the embodiment of the present invention does not limit the present invention, and any modifications, equivalent replacements and improvements made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims (6)

1. A design method of a TE01 and TM11 circular waveguide dual-mode filter is characterized by comprising the following steps: the device comprises two hollow circular cavities, an input coupling cut-off waveguide, an output coupling cut-off waveguide, a cavity and a cover plate; the two hollow circular cavities are respectively connected with an input coupling cut-off waveguide and an output coupling cut-off waveguide, the coupling cut-off waveguide is connected with the two hollow circular cavities, the cavity is provided with a groove, the two hollow circular cavities, the input coupling cut-off waveguide, the output coupling cut-off waveguide and the coupling cut-off waveguide are correspondingly connected in shape and size and are used for being embedded, and the cover plate is fixed on the cavity through screws to form sealing.

2. The method for designing a TE01 and TM11 circular waveguide bimodal filter as claimed in claim 1, further comprising: the diameters of the two hollow circular cavities are respectively changed, so that the TE01 and TM11 modes can be simultaneously resonated at the required central frequency.

3. The method for designing a TE01 and TM11 circular waveguide bimodal filter as claimed in claim 1, further comprising: the longitudinal-transverse diameter ratio of the two hollow circular cavities is changed respectively, the circular cavities are changed into the elliptical cavities to form perturbation, two modes of TE01 and TM11 are separated to generate a coupling relation, a coupling bandwidth required by the design of the filter is formed, and a transmission zero point is generated in a non-resonant mode of the two hollow circular cavities.

4. The method for designing a TE01 and TM11 circular waveguide bimodal filter as claimed in claim 1, further comprising: the width and the length of the input coupling cut-off waveguide and the output coupling cut-off waveguide are adjusted, and the positions of the centers of the two hollow circular cavities are deviated, so that the input bandwidth and the output bandwidth required by the design of the filter are met.

5. The method for designing a TE01 and TM11 circular waveguide bimodal filter as claimed in claim 1, further comprising: the width and the length of the coupling cut-off waveguide connecting the two hollow circular cavities and the position deviating from the circle centers of the two hollow circular cavities are adjusted, so that the coupling bandwidth required by the design of the filter is met.

6. The design method of TE01 and TM11 circular waveguide dual-mode filter according to any of claims 2 to 5, further comprising: and (3) performing integral modeling simulation on HFSS or CST (hybrid finite impulse response) simulation software, and repeatedly adjusting for multiple times until the bandwidth, out-of-band rejection and return loss of the filter meet the design requirements.

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