Microstrip filter with controllable transmission zeros

Abstract

The invention discloses a microstrip filter with controllable transmission zeros. The lower surface of a dielectric substrate (1) of the microstrip filter is completely covered with a metal layer, and a first input and output feeder (21), a first short-circuit stub (31), a first resonator (41), a second short-circuit stub (32), a second resonator (42), a third short-circuit stub (33), a third resonator (43), a fourth short-circuit stub (34) and a second input and output feeder (22) of a metal layer of the upper surface of the dielectric substrate (1) are connected in sequence. The first resonator (41), the second resonator (42) and the third resonator (43) are formed by connecting three inverted-T-shaped microstrip lines, each resonator can generate one transmission zero, and the positions of the transmission zeros can be controlled according to the lengths of open-circuit stubs on the resonators. The microstrip filter has the advantages of being convenient to process and low in cost and weight; meanwhile, the number of the transmission zeros is large, the out-of-band rejection performance and frequency selectivity of the microstrip filter are improved, and the microstrip filter can be widely applied to wireless communication systems.

Description

technical field [0001] The invention relates to a microstrip filter with controllable transmission zero point, which belongs to the technical field of microwave passive devices. Background technique [0002] Filter is a key device in radio technology, its role is to filter out unwanted frequency components, and it is widely used in various commercial and military fields, such as radar systems, wireless communication systems, and medical imaging systems. In recent years, various wireless communication systems have developed rapidly, such as wireless local area network, mobile communication, and global positioning system, and there is certain interference in the frequency spectrum between the systems. Therefore, more and more stringent index requirements are put forward for microwave filters. For example, the filter in the microwave integrated circuit needs to be miniaturized, which can reduce the size of the system and save cost; the mobile communication base station require...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to propose a microstrip filter with controllable transmission zeros, which overcomes the disadvantages of the existing filter with few transmission zeros, difficult position control, and sensitivity to coupling between resonators.

Images