Ultra-miniature high-Q filters and duplexers using FBAR technology

An ultra-miniature PCS duplexer uses thin-film bulk wave acoustic resonator (FBAR) technology. FBAR resonators are made using aluminum nitride for the piezoelectric material and silicon as the substrate. It has better than -52 dB rejection for the receive (Rx) filter in the transmit (Tx) band and pass-band insertion losses are on the order of 2 dB (Tx) and 3 dB (Rx). Performance is comparable to that of much larger ceramic duplexers.