On October 20, 2021, Qualcomm announced its UltraBAW™ family of bulk acoustic wave RF filters suitable for the higher frequencies and wider fractional bandwidths of the most demanding 5G and Wi-Fi 6E bands up to 7.2 GHz. 

RF Filter and RF front-end (RFFE) module suppliers Murata, Skyworks, Qorvo, Broadcom, Taiyo Yuden and others are racing to fill gaps in their RF product portfolios to support the broadest possible range of 4G, 5G and Wi-Fi 6/6E bands in smartphones and other wireless devices.  Suppliers of bulk acoustic wave (BAW) filters such as Broadcom’s FBAR (film bulk acoustic resonator) and Qorvo’s SMR-BAW (solidly mounted resonator) designs have added dopants to their piezoelectric materials to improve the electromechanical coupling coefficient for higher frequencies and bandwidths.

Up until now Qualcomm has not publicly acknowledged that it has RF filters for the 5G and Wi-Fi bands above 5 GHz.  With the announcement, Qualcomm has said that it is shipping samples of its new UltraBAW filters to customers and will begin volume production in 2022.   Qualcomm will not limit products to stand-alone filters; for example, Qualcomm’s QPM6679 PA module (announced in February 2021) will incorporate UltraBAW, as will other RFFE modules including diversity and Wi-Fi modules from Qualcomm.

The company has not said much about the technical details of UltraBAW.  To paraphrase a spokesperson, “UltraBAW uses an SMR-BAW style resonator in aluminum nitride.  We use a unique set of materials for the substrate, resonator and electrodes, which can significantly impact the characteristics of the filter’s frequency response.”  Qualcomm says that UltraBAW’s substrate construction with no air gap under the resonators gives UltraBAW superior heat handling capabilities compared to Broadcom’s popular FBAR filters, important in the relatively high RF power transmit chains of smartphones..

Qualcomm surely developed UltraBAW as an evolution of their previous SMR-BAW filters by doping the aluminum nitride piezoelectric material they use.  Qualcomm also may have switched from silicon to piezo-on-insulator substrates as used in their UltraSAW filters.   In any case, Qualcomm’s UltraBAW filters probably at least match competitors’ latest filters for challenging new bands such as 5G n77 and the new Wi-Fi 6E bands from 5 GHz to 7.2 GHz.  With UltraBAW, Qualcomm has reassured its customers and investors that it will maintain its ability to supply complete cellular radio modem solutions from baseband to antenna as new 5G and Wi-Fi 6 devices ramp. 

Strategy Analytics subscribers with access to the RF & Wireless Components service can learn more about competitors and positioning in the market for filters and RF modules by viewing Acoustic Filters: Critical to Future RF FE Integration (PPT), also available as a video presentation, and can contact the author with any questions.