Constant-bandwidth broadband filter with electrically-adjusted transmission zero point

Abstract

The invention discloses a constant-bandwidth broadband filter with an electrically-adjusted transmission zero point. The constant-bandwidth broadband filter comprises a micro-strip dielectric substrate (1), a metal grounding plate (2), a short-circuit branch loading resonator (3), a coupling feeder line (4), a grounding hole (5), a capacitance variable diode (6) and a DC biasing circuit (7). A folded short-circuit branch loading resonator is adopted to increase a current path, the resonance frequency is reduced, and a folding double-feeder structure is loaded on the inner side, so that the broadband filter is compact in structure and small in size. A capacitance variable diode control source is coupled with a load, and the capacitance value of the capacitance variable diode is adjusted through a direct current bias circuit, so that the position and the quantity of transmission zero points are changed, and the selective performance of the broadband filter is improved. The performance ofthe passband is not affected, and the constant bandwidth is kept, so that the performance stability of the filter is ensured.

Description

technical field [0001] The invention belongs to the technical field of electronic devices, and in particular relates to a micro-broadband filter, which can be used in radio frequency front ends of wireless communication systems and satellite communication systems. Background technique [0002] The vigorous development of global communication technology makes satellite communication, radar tracking, detection guidance and remote sensing technology more and more rely on microwave and millimeter wave technology. With the increasing number of microwave and millimeter wave communication services, spectrum resources are increasingly tight, and frequency band resources are divided more finely, so the requirements for wireless terminal equipment become very stringent. High-performance, miniaturized, low-cost, and easy-to-integrate microwave filters have become a research hotspot in the field of microwave and radio frequency today. Traditional filters, such as Butterworth and Chebys...

AI Technical Summary

Problems solved by technology

However, the transmission zero of a multimode resonator tends to be adjusted as the passband of the resonator is adjusted, and the in-band characteristics will also change accordingly

This point in the filter design will lead to poor filter design versatility, that is, it must be re-selected and designed according to different requirements, which cannot meet the increasing filter design requirements of modern communication systems.

[0004] None of the existing filters can meet the requirements that the in-band parameters are constant, the inherent bandwidth is not affected by other factors, and the filter selection performance can be adjusted and changed through the circuit without affecting the parameters in the passband according to the needs of different scenarios.

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