Abstract
A novel enlarging fractional bandwidth (FBW) technique for
acoustic-wave-lumped-element resonator (AWLR) -based bandpass filters is
present. The new technique is based on a series of matching inductors
that replace the parallel or series acoustic wave (AW) resonators of AW
filters to beak the bandwidth constraint of the ladder-type structure.
In addition, the transmission response analysis of the proposed
AWLR-based filter is provided. A prototype of the AWLR-based filter is
fabricated and tested to validate the proposed FBW widening technique.
The measured insertion loss, FBW, and out-of-band rejection are 1.5dB,
1.63kt2 (kt2 is the electromechanical coupling coefficient of the AWR),
and 38dB, respectively.