Hybrid Bulk Acoustic Wave Structure for Temperature Stability of LTE Applications
Journal
IEEE Microwave and Wireless Components Letters (MWCL)
Date
2013.09.30
Abstract
A novel structure of hybrid bulk acoustic wave (BAW) resonator with low temperature coefficient of frequency (TCF) is presented. Implemented with a pair of quarter-wave reflectors on air gap reflector, the hybrid BAW resonator exhibits low TCF of -11.5ppm/℃ as well as high effective electro-mechanical coupling coefficient (kt2) of 5.1％ at the frequency of 2.5 GHz. The hybrid BAW resonator also shows high Q-factors of 1627 and 1842 at resonance and anti-resonance frequency, respectively. RF duplexer configured with the hybrid BAW resonators is provided as well. The fabricated RF duplexer for long term evolution (LTE) band-7, which is should be designed to prevent the co-existence problem with WiFi having extremely narrow band gap of 0.7％, achieves high attenuation of 36.8dB and low insertion loss of 2.4dB.
Reference
IEEE Microwave and Wireless Components Letters, wol.23,No.9,pp.453-455,2013