Trapezoidal structure sound wave narrow-band band-pass filter

Abstract

The invention discloses a trapezoidal structure sound wave narrow-band band-pass filter and relates to the field of band-pass filters. The trapezoidal structure sound wave narrow-band band-pass filter comprises a first trapezoidal structure sound wave narrow-band band-pass filter unit and / or a second trapezoidal structure sound wave narrow-band band-pass filter unit. The first trapezoidal structure sound wave narrow-band band-pass filter unit comprises a first resonator connected onto a series-connection branch, a second resonator connected onto a parallel-connection branch and a third resonator located on the series-connection branch and connected with the first resonator in parallel. The second trapezoidal structure sound wave narrow-band band-pass filter unit comprises a fourth resonator connected onto the series-connection branch, a fifth resonator connected onto the parallel-connection branch and a sixth resonator located on the parallel-connection branch and connected with the fourth resonator in series. The trapezoidal structure sound wave narrow-band band-pass filter can well solve the problem that an existing band-pass filter sacrifices insertion loss in a sound wave filter pass band or reduce the roll-off performance when achieving ultra-narrow bandwidth.

Description

technical field [0001] The invention relates to a band-pass filter, in particular to a trapezoidal structure acoustic wave narrow-band band-pass filter. Background technique [0002] With the rapid popularization of wireless communication equipment, there is an increasing demand for high-frequency filters with small size, light weight and high performance. Acoustic filters fabricated on a single wafer have been widely accepted by the market. The resonators that make up this high-performance acoustic wave filter mainly include: FBAR (Film Bulk Acoustic Resonator, thin film bulk acoustic resonator), SMR (Solidly Mounted Resonator, solid-state assembly resonator) and SAW (Surface Acoustic Wave, surface acoustic wave resonator) device). The topological structures of filter circuits designed using resonators mainly include ladder-like structure and grid-like structure. At present, in the design of high-performance acoustic wave filters and duplexers, the design method of trapez...

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Problems solved by technology

[0008] The purpose of the present invention is to provide a trapezoidal structure acoustic wave narrowband bandpass filter, which can better solve the problem of sacrificing the insertion loss in the passband of the acoustic wave filter or reducing the efficiency of the filter when the existing bandpass filter realizes ultra-narrow bandwidth. Problems with roll-off performance

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