High Rejection, 160MHz Bandwidth, High Q-factor 6 GHz RF Filters for Wi-Fi 6E manufactured in a Novel BAW Process

Abstract

Wi-Fi 6/6E uses 160 MHz channels in UNII-5/6/7/8 bands in 5-7GHz spectrum for maximizing data rates. A critical challenge for Wi-Fi 6E RF filters is low insertion loss in the 160MHz UNII-5 transmit band while adequately rejecting UNII bands 1, 2C, 3 & 4, which end only 50MHz below the first channel of the UNII-5 band. A 160MHz Wi-Fi 6E bulk acoustic wave (BAW) filter with UNII-5 average pass band insertion loss better than 2dB and 60dB rejection in the UNII-4 band is reported. A unique BAW device fabrication process capable of utilizing a wide variety of piezoelectric thin films is used to manufacture this challenging filter. Fabricated resonators show a maximum quality factor of 2500.