Quasi-elliptic filtering character frequency selecting surface

Abstract

The invention is a quasi-elliptic filter characteristic frequency selection surface, an ultrathin novel frequency selection surface with quasi-elliptic filter characteristic, based on substrate integrated waveguide cavity cascading technique, and the structure is made on a multilayer substrate formed by laminating three layers of microwave plates and having four metal surface layers and three medium layers, where the top and bottom metal surfaces are made with periodical square annular slots of the same size. And the intermediate metal surface is made with periodical square annualr slots of the other size which coincides the centers of the square annular slots on the top and bottom surfaces, three medium layers are filled in between the four metal surface layers, and a series of metalized through holes are arranged at regular intervals around each periodical square annular slot unit on the ready-laminated multilayer substrate so as to form a substrate integrated waveguide cavity equivalent to traditional metal cavity. As compared with common SMD or slot type multiscreen cascaded frequency selection surface, it first implements quasi-elliptic filter performance with high selectivity.

Description

technical field [0001] The invention is an ultra-thin novel frequency selective surface with quasi-elliptic filter characteristics based on the substrate integrated waveguide cavity cascading technology, and belongs to the field of microwave technology. Background technique [0002] Frequency selective surfaces (FSS) are widely used in engineering applications. FSS has good selectivity for the transmission and reflection of electromagnetic waves. It has all-pass characteristics for electromagnetic waves in its passband, and total reflection characteristics for electromagnetic waves in its stopband. It has a spatial filtering function. In the microwave field, FSS can be used in the frequency band multiplexer of the communication satellite system, and the communication capacity can be expanded by using multi-feed configuration. Another main use is to make radomes for shielding and stealth of radar antennas in aerospace. High performance waveguide filters can also be fabricat...

AI Technical Summary

Problems solved by technology

The cascaded multi-layer FSS is filled with a dielectric layer used as an impedance transformer, but the thickness of the dielectric layer is about a quarter of the wavelength corresponding to the center frequency of the working frequency band, which makes the thickness of the entire FSS structure very large, limiting it in many Use in practical applications

Moreover, the current various multi-screen cascading methods cannot achieve cross-coupling, so there are no reports of frequency selective surfaces that achieve elliptical or quasi-elliptic filtering characteristics.

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