A notch frequency tunable ultra-wideband filter with improved band-stop characteristics

Abstract

The invention discloses a notch frequency adjustable ultra-wideband filter with improved band elimination characteristics. The notch frequency adjustable ultra-wideband filter comprises an upper signal layer comprising a dielectric substrate, an input / output port, a polygonal transmission unit and a short circuit branch; a middle metal grounding layer comprising a polygonal defect unit; a bottom signal layer comprising a dielectric substrate, an input / output port, a polygonal transmission unit and two open circuit branches, wherein one open circuit branch is arranged in a rectangular defect unit close to the input / output port and is connected with the middle metal grounding layer through an adjustable capacitor, and the two transmission units and the defect unit are coaxially arranged. Thefilter achieves the high coupling function of the coupling transmission line by utilizing a polygonal defected ground coupling structure so as to achieve the ultra wide band, achieve the out-of-bandharmonic suppression by utilizing the open circuit branches and the short circuit branch, achieve the notch characteristic in the bandwidth by utilizing the open circuit branches at the port and change the notch frequency by changing the capacitance value of the capacitor. The notch frequency adjustable ultra-wideband filter is simple in design, convenient to process and low in cost.

Description

technical field [0001] The invention belongs to the technical field of microwave transmission devices, in particular to an ultra-wideband filter with adjustable notch frequency and improved band-rejection characteristics. Background technique [0002] With the rapid development of wireless communication technology, people put forward higher requirements for the data transmission rate and confidentiality of wireless communication systems. UWB technology emerges as a key technology. In 2002, the Federal Communications Commission of the United States agreed to use 3.1GHz to 10.6GHz for commercial use, which opened the door to the rapid development of ultra-wideband technology. Because UWB technology has the advantages of low cost, fast transmission rate, good security, and low power consumption, UWB technology has shown huge market value and broad application prospects. UWB filter is an important part of UWB communication system, and its performance has a great influence on t...

AI Technical Summary

Problems solved by technology

[0003] At present, there are many ways to realize ultra-wideband filters, mainly including: 1. Using high-pass filter and low-pass filter cascaded to realize ultra-wideband, but its structure is complex and bulky, which is not conducive to integration; 2. Loading transmission lines based on short-circuit stubs structure, this type of filter has a large size and poor selectivity; 3. It adopts a multi-mode structure, but this structure is complex in design, difficult to process, and poor in reliability

At present, the methods of realizing notch in the passband of the filter mainly include: 1. Using an asymmetric input / output structure to generate a zero point, but this structure is only suitable for a parallel coupling structure, and the harmonics are difficult to suppress, and the application is limited; 2. Loaded trap resonator structure, but the structure is complex and difficult to process

Images