A kind of ultra-wideband filter

Abstract

The invention relates to an ultra-wideband filter. The ultra-wideband filter includes a metal microstrip, an interlayer dielectric substrate, and a metal formation arranged sequentially from top to bottom. The metal microstrip includes a metal plate and a metal microstrip structure arranged on the metal plate. The metal microstrip structure is in the shape of a symmetrical plane. The left and right mirrors are symmetrical, the first port connection line is connected to the external device, the energy sent by the external device is transmitted to the first U-shaped meandering node through the first port connection line, and the energy is transmitted to the second U-shaped meandering node after high frequency filtering A loading branch, after being selected by the first loading branch, is transmitted to the input coupling section, and after being coupled by the input coupling section, it is sequentially transmitted to the six-mode resonator, the output coupling section, the second loading branch, the second U-shaped meandering section, the second port cable. The invention has ultra-wide bandwidth, high selectivity and high stop band suppression.

Description

technical field [0001] The invention relates to the field of filter design, in particular to an ultra-wideband filter. Background technique [0002] With the rapid development of modern communication systems, broadband and high speed have become its main development trend. This broadband and even ultra-wideband communication technology was born. Ultra-wideband communication system has attracted a lot of research attention due to its high transmission rate, strong anti-interference ability, low power consumption, etc., and ultra-wideband bandpass filter, as its key device, has also become the focus and hotspot of research. According to the U.S. Federal Communications Commission (FCC) regulations, an ultra-wideband filter refers to a filter with a relative bandwidth greater than 20%. A variety of ultra-wideband filter design methods have been proposed. For example, ultra-wideband filters can be obtained by cascading high-pass and low-pass filters. However, the physical size ...

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Problems solved by technology

[0003] The ultra-wideband filter designed by the above methods has a typical common problem, that is, it is difficult to take into account ultra-wide bandwidth, high selectivity and high out-of-band rejection at the same time. This problem has also become the bottleneck of the application of ultra-wideband filters in high-standard communication systems.

In order to improve the above out-of-band performance, some research methods have been proposed: in the patent "A Harmonic Suppression Ultra-Wideband Filter Based on DGS Structure", by introducing a defective ground structure (DGS), that is, etching patterns in the metal formation so that the resistance Multiple transmission zeros are generated in the band, which improves the selectivity and also improves the out-of-band suppression, but this method needs to destroy the formation structure, and it is not conducive to simplifying the processing; in the patent "a wide stop band and high selectivity In "Ultra-wideband bandpass filter structure", a variety of compact microstrip resonant units are used to design a highly selective ultra-wideband filter, but the structure is relatively complicated, and multiple short-circuit vias need to be manufactured, which is also not conducive to simplification. processing

In addition, it is worth noting that although different methods have been used to improve the out-of-band performance, the stop-band suppression level of the resulting ultra-wideband filter is still unsatisfactory, only 20-30dB, and there is still a certain distance from the high-performance system requirements

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