Coaxial cavity dual-band filter based on stepped impedance structure

Abstract

The invention discloses a coaxial cavity dual-band filter based on a stepped impedance structure. The filter provided by the invention is formed by coupling of several stepped impedance coaxial cavity resonator units. Each stepped impedance coaxial cavity resonator unit is composed of three parts, namely two rod-shaped solid metallic conductors, a tubular metallic wall and a filler. The filler is air and is positioned in a resonant cavity between the tubular metallic wall and the rod-shaped solid metallic conductors. The upper and lower ends of the tubular metallic wall are provided with outer cover plates for sealing the resonant cavity. The several stepped impedance coaxial cavity resonator units are arranged in a linear parallel structure. The two rod-shaped solid metallic conductors are two coaxial cylinders with different diameters and are divided into a lower conductor cylinder and an upper conductor cylinder. The two conductor cylinders are connected in series up and down. The lower conductor cylinder is electrically connected with a feeder line of an input or output port. According to the invention, two passbands are realized by the stepped impedance coaxial cavity resonator units; passband frequency ratio adjustable range is large; the size of the filter is small; and the structure of the filter is simple and reasonable.

Description

technical field [0001] The invention relates to a dual-band filter in the field of wireless communication, in particular to a coaxial cavity dual-band filter based on a step impedance structure. Background technique [0002] Due to the rapid development of wireless communication technology and the increasing demand for wireless communication, 2G, 3G, and 4G networks coexist in the market today. Many wireless terminals, such as mobile phones, tablet computers, etc., are designed to be compatible with multiple communication standards. , which allows end users to enjoy services provided by different operators at the same time. Multi-frequency filters realize multiple passbands or stopbands on one circuit at the same time, which can significantly reduce circuit size and cost, so it is a research hotspot. In actual industrial production, the cavity filter is the most commonly used, because compared with the planar filter, the cavity filter has a higher power capacity. In cavity...

AI Technical Summary

Problems solved by technology

This method of inserting zero points in one passband to achieve two passbands results in a smaller passband frequency than the adjustable range; and it is necessary to design a structure in which many resonators are strictly juxtaposed to form a matrix, which makes the filter volume large and the shape Can not be adjusted flexibly

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