High-performance SAW filter with a novel wave-weighted transducer design
RF filter is an indispensable device for signal transmission frequency selection and noise interference filtering in mobile communication.Based on piezoelectric thin-films multilayer,surface acoustic wave filters have been widely used due to their high rectangle factor and low loss.However,the inherent transverse modes of the resonators can greatly deteriorate the filter performance.Here a novel wave-weighted interdigital-transductor design was proposed to suppress the transverse modes without deteriorating the performance of the resonator,where a sinusoidal function was used as the weighted envelope curve for the crossover length.A high-performance filter was successfully designed and fabricated with dimensions of 1.1 mm×0.9 mm×0.55 mm.The filter employs cascading resonators based on the proposed wave-weighted design in a ladder topology configuration.The fabricated filter exhibits a high performance with a central frequency of 2.593 GHz,a relative bandwidth of 8.8%and an insertion loss of 0.52 dB.Besides,the measured results are in good agreement with the simulation results.
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维普
