Differential dual-frequency band-pass filter with high selectivity

Abstract

The invention discloses a differential dual-frequency band-pass filter with high selectivity. By the differential dual-frequency band-pass filter with high selectivity, the problem of poor out-of-bandselectivity in design of the differential dual-frequency band-pass filter is solved. A first uniform impedance resonant ring, a second uniform impedance resonant ring, an input microstrip line and anoutput microstrip line are arranged on an upper surface of a dielectric substrate, the first uniform impedance resonant ring and the second uniform impedance resonant ring are embedded to each other,the input microstrip line and the output microstrip line are symmetric to each other, and a step impedance gap line comprising a central loading branch is arranged on a lower surface. L-shaped open-circuit branches are loaded on the input/output microstrip lines, the central loading branch of the gap line passes through a projection line of a center of the dual-frequency band-pass filter and is arranged at the center of a T-shaped gap line, and the dual-frequency band-pass resonator is of a folded and embedded structure. By adding a transmission zero point mode, the frequency selectivity is improved, the space utilization rate and the integration are effectively improved, the design complexity is reduced, and the differential dual-frequency band-pass filter has the advantages of small introduction noise, high interference-resistant capability and small loss and is widely applied to a mobile wireless communication system.

Description

technical field [0001] The invention belongs to the field of microwave and radio frequency technology, and further relates to a differential dual-frequency bandpass filter in the field of microwave and radio frequency, in particular to a differential dual-frequency bandpass filter with high selectivity, which is applied to the radio frequency front end of a wireless communication system. Background technique [0002] With the rapid development of modern wireless communication systems, filters are more and more widely used in the field of wireless communication, and play an increasingly important role in radio frequency front-ends such as radar systems. A filter with good working characteristics can filter out the noise generated by the system and the interference from other channel signals, and can achieve the performance index of the system design while ensuring the stability of the entire wireless communication system. Nowadays, miniaturization and high performance have be...

AI Technical Summary

Problems solved by technology

However, the disadvantages of this design are that there are no obvious transmission zeros on the left and right sides of the third passband and the fourth passband of the filter, the frequency band selectivity is poor, and the operating loss is also large, so it is still necessary room for improvement

However, because there is no transmission zero on the left side of the first filtering passband of the filter, it has the defects of poor selectivity and low out-of-band rejection

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