Ultra-wideband ladder filter using SH0 plate wave in thin LiNbO3 plate and its application to tunable filter

Michio Kadota, Shuji Tanaka

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


A cognitive radio terminal using vacant frequency bands of digital TV (DTV) channels, i.e., TV white space, strongly requires a compact tunable filter covering a wide frequency range of the DTV band (470 to 710 MHz in Japan). In this study, a T-type ladder filter using ultra-wideband shear horizontal mode plate wave resonators was fabricated, and a low peak insertion loss of 0.8 dB and an ultra-large 6 dB bandwidth of 240 MHz (41%) were measured in the DTV band. In addition, bandpass filters with different center frequencies of 502 and 653 MHz at 6 dB attenuation were numerically synthesized based on the same T-type ladder filter in conjunction with band rejection filters with different frequencies. The results suggest that the combination of the wideband T-type ladder filter and the band rejection filters connected with variable capacitors enables a tunable filter with large tunability of frequency and bandwidth as well as large rejection at the adjacent channels of an available TV white space.

Original languageEnglish
Article number7103533
Pages (from-to)939-946
Number of pages8
JournalIEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Issue number5
Publication statusPublished - 2015 May 1

ASJC Scopus subject areas

  • Instrumentation
  • Acoustics and Ultrasonics
  • Electrical and Electronic Engineering


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