An Improved Isolation W-CDMA Ladder BAW-SMR Filter

Abstract

This paper presents a ladder BAW-SMR filter with improved isolation for application in W-CDMA reception band (2.11 -2.17 GHz). The high isolation is achieved by placing one transmission zero at the W-CDMA transmission band (1.92 -1.98 GHz). It could be implemented thanks to a design technique that employs bonding wires to introduce transmission zeros. This technique enables to increase the rejection of ladder BAW filters. The filter presents: 1.6 dB of insertion loss, -16 dB of return loss and isolation higher than 35 dB at TX band (1.92 -1.98 GHz).