Branch knot loading compact type microstrip filter

Abstract

The invention provides a branch knot loading compact type microstrip filter. Metal circuits with left-right symmetrical patterns are arranged on a metal surface layer. The metal circuits comprise bent input-output ports which are left-right symmetrical and arranged in a Z shape, source end and load loading transmission lines and input-output couplers which are inwardsafter bending. The source end and the loading transmission lines are connected in a bending mode. The branch knot loading compact type microstrip filter further comprises a T-shaped opening circuit loading upper transmission line, a T-shaped opening circuit loading lower transmission line and left-right-parallel even transmission line resonance units of a downward bent structure. The T-shaped opening circuit loading upper transmission line and the T-shaped opening circuit loading lower transmission line are located at a middle position and of a cross-shaped crossing structure and arranged vertically. The branch knot loading compact type microstrip filter solves the problem that a traditional microstrip filter is large in size, low in stop band restrain level and high in loss.

Description

technical field [0001] The invention relates to a compact low-loss microstrip filter, in particular to a branch-loaded compact microstrip filter. Background technique [0002] In microwave integrated circuits, microstrip is the most widely used transmission line, and its structure is convenient for external microwave solid devices. Microstrip patch resonators are widely used to design filters. A common microstrip filter structure is a uniform parallel line coupling structure. The obvious disadvantage of this structure is that it is bulky and has serious harmonic interference problems. [0003] After searching the relevant literature, it was found that in 2003, L.Zhu et al. published the Compact Microstrip Bandpass Filter With Two Transmission Zeros Using a Stub Tapped Half Wavelength Line Resonator in the journal IEEE Microwave and Wireless Components Letters. The method of uniform transmission line resonant cavity realizes the out-of-band limited transmission zero po...

AI Technical Summary

Problems solved by technology

The obvious disadvantage of this structure is that it is bulky and has serious harmonic interference problems.

[0003] After searching the relevant literature, it was found that in 2003, L.Zhu et al. published the Compact Microstrip Bandpass Filter With Two Transmission Zeros Using a Stub Tapped Half Wavelength Line Resonator in the journal IEEE Microwave and Wireless Components Letters. The method of uniform transmission line resonant cavity realizes the out-of-band limited transmission zero point of the filter and enhances the suppression of the filter, but the open-circuit loading line is large in size, which is not conducive to the miniaturization of the filter and device integration

Images