Four-mode substrate integrated waveguide broadband filter

Abstract

The invention provides a four-mode substrate integrated waveguide broadband filter. The invention mainly aims to realize the filter bandwidth spread of a substrate integrated waveguide single-cavity multi-mode structure. The four-mode substrate integrated waveguide broadband filter of the invention comprises a dielectric substrate, a lower-layer metal patch, an upper-layer metal patch, first metallized through holes, second metallized through holes, an etched rectangular slit structure, metallized blind holes and microstrip feed lines. On the basis of a substrate integrated waveguide dual-moderesonant cavity of which the opposite angles have second metallized through hole infinitesimal disturbance, the rectangular slit structure is formed on the upper-layer metal patch through etching, sothat fundamental mode frequency increase can be realized; the four metallized blind holes are additionally formed at the periphery of the rectangular slit structure, so that three-order-mode patternfrequency decrease can be realized; and therefore, four mode frequencies can be adjacent to each other. External coupling is realized by means of a microstrip feeding mode, and therefore, the design of the four-mode substrate integrated waveguide broadband filter can be realized. The bandwidth of the filter of the invention is broadened; and the selection characteristic of the pass-bands of the filter is improved. The filter can be applied to a radio frequency wireless communication system.

Description

technical field [0001] The invention belongs to the field of microwave technology, and relates to a substrate-integrated waveguide filter, in particular to a four-mode substrate-integrated waveguide broadband filter, which can be used for a radio frequency front end of a wireless communication system. Background technique [0002] In modern microwave wireless communication systems, passive components such as filters and duplexers play a very important role. Traditional microwave and millimeter wave filters usually use waveguide or microstrip transmission line structures, but they have their own shortcomings that are difficult to overcome. For planar structure filters such as microstrip or stripline, although they have the advantages of small size, light weight, and easy integration with board-level circuits, they have the disadvantages of low power capacity, large loss, and electromagnetic compatibility problems caused by semi-open structures. Disadvantages; for metal waveg...

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Problems solved by technology

[0004] For example, in 2017, Chen Weidong and others published "Miniaturized Dual-Band Filter Using Dual-Capacitively Loaded SIW Cavities" in IEEE Microwave and Wireless Components Letters (Vol.27No.7pp.344-346, 2017), and proposed a method based on Capacitively loaded substrate-integrated waveguide dual-passband filter, but because the high-order mode harmonics appear near the second passband, the filter's high-frequency out-of-band selectivity is not excellent, and because each passband only It is composed of two modes, so the relative bandwidth of the filter is relatively narrow

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