Title :
High frequency resonators with wide bandwidth using SH0 mode plate wave in thin LiNbO3
Author :
Kadota, Mitsuhiro ; Esashi, Masayoshi ; Tanaka, Shoji ; Kuratani, Yasuhiro ; Kimura, Tomohiro
Author_Institution :
Micro Syst. Integration Center, Tohoku Univ., Sendai, Japan
Abstract :
Currently, an ultrawide band resonator used for a tunable filter with a wide tunable range is strongly required, because a mobile phone with multi-bands and a cognitive radio system require such a tunable filter to simplify their wirelss front-end circuits. The authors developed resonators with ultrawide bandwidths of 26% to 29% and large impedance ratios of 92 to 98 dB between resonance (fr) and anti-resonance frequencies (fa) using a 0-th shear horizontal (SH0) mode plate wave in a 28-30°YX-LiNbO3 plate. However, the resonators were of low frequency as fr = 1.8 MHz and fa = 2.3 MHz and suffer from ripples due to transverse mode between fr and fa. In this study, high frequency SH0 mode plate wave resonators (fr = 440 ~ 560 MHz) with a wide bandwidth and a large impedance ratio and without ripples have been fabricated using an ultrathin LiNbO3 plate and an apodized interdigital transducer.
Keywords :
acoustic impedance; acoustic resonance; interdigital transducers; lithium compounds; plates (structures); surface acoustic wave resonator filters; LiNbO3; SAW resonator; antiresonance frequencies; cognitive radio system; impedance; interdigital transducer; mobile phone; shear horizontal mode plate wave; tunable filter; ultrathin plate; ultrawide band resonator; Bandwidth; Couplings; Gratings; Impedance; Lithium niobate; Resonant frequency; Resonator filters; 0-th shear horizontal mode; apodized IDT; high frequency; large impedance ratio; plate wave; wideband;
Conference_Titel :
Ultrasonics Symposium (IUS), 2013 IEEE International
Conference_Location :
Prague
Print_ISBN :
978-1-4673-5684-8
DOI :
10.1109/ULTSYM.2013.0428