Low loss and high isolation techniques for high power RF acoustic devices

Requirements for radio frequency (RF) devices in mobile phones have been getting more stringent, especially in multiband / carrier aggregation systems constructing many RF components. In this paper, we discuss two important items for RF acoustic devices developed by our team. First, we introduce the heat radiation effect and temperature compensation technology to suppress the temperature drift of acoustic devices for lower insertion loss. Heat sink effect of substrates and package, and temperature compensated film bulk acoustic resonator (FBAR) devices employing SiOF is introduced. Then, how to suppress the signal leakage from transmission (Tx) to reception (Rx) of the duplexer using signal cancellation technique is discussed, and SAW Band 8 duplexer is demonstrated as an example.