An N41-Band Bandpass BAW Filter Chip for Mobile Communications Based on FBARs

A bulk acoustic wave (BAW) filter for the N41 band (2535 MHz-2655 MHz) is designed in this paper. This design is a ladder filter based on the one-dimensional Mason circuit model of the film bulk acoustic resonator (FBAR). In order to improve the accuracy of the simulation results, the acoustic-electro magnetic joint simulation is performed, and the results are compared with the circuit model. The filter designed in this paper has a low insertion loss (less than 2.0 dB), a high out-of-band rejection (greater than 42 dB), a high-power capacity (greater than 30 dBm), and a small size (1.1×0.9m m²).