Improvement of insertion loss of band pass tunable filter using SAW resonators and GaAs diode variable capacitors

Michio Kadota, Masayoshi Esashi, Shuji Tanaka, Yasuyuki Ida, Tetsuya Kimura

Research output: Chapter in Book/Report/Conference proceedingConference contribution

6 Citations (Scopus)

Abstract

Tunable filters with a wide band tunable range are required for mobile phones with multi-bands and cognitive radio systems to simplify their circuits. Previously, the authors prototyped a band pass tunable filter, which continuously changes frequency from 1734 to 1844 MHz (6.1%) using surface acoustic wave (SAW) resonators and Si diode variable capacitors (varicap). However, the insertion loss was large compared with calculated one because the Q factor of the Si diode varicap was as low as 1 at 1.8 GHz. In this study, the authors improved the insertion loss of the tunable filter using GaAs varicaps. Compared with the Si varicap, the GaAs varicap has a higher Q factor of about 41 at 1.8 GHz. The authors fabricated a tunable filter composed of two SAW resonators and the GaAs varicaps instead of the Si varicaps on a printed circuit board (PCB). As a result, the insertion loss was drastically improved by 12 dB at the maximum, and the frequency characteristic approached the calculated one. The tunable range was also improved from 6.1% to 6.8%.

Original languageEnglish
Title of host publication2013 IEEE International Ultrasonics Symposium, IUS 2013
Pages1668-1671
Number of pages4
DOIs
Publication statusPublished - 2013 Dec 1
Event2013 IEEE International Ultrasonics Symposium, IUS 2013 - Prague, Czech Republic
Duration: 2013 Jul 212013 Jul 25

Publication series

NameIEEE International Ultrasonics Symposium, IUS
ISSN (Print)1948-5719
ISSN (Electronic)1948-5727

Other

Other2013 IEEE International Ultrasonics Symposium, IUS 2013
CountryCzech Republic
CityPrague
Period13/7/2113/7/25

Keywords

  • Band pass tunable filter
  • GaAs diode variable capacitor
  • Insertion loss
  • SAW

ASJC Scopus subject areas

  • Acoustics and Ultrasonics

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