Title :
An SAW filter employing weighted reflectors and a multi-strip coupler
Author :
Kaneda, Y. ; Tajima, M. ; Omori, T. ; Hashtmoto, K. ; Yamaguchi, M. ; Tsutsumi, J. ; Ikata, O. ; Satoh, Y.
Author_Institution :
Fujitsu Media Devices Ltd., Japan
Abstract :
This paper deals with a miniaturised surface acoustic wave (SAW) filter employing two IDTs, two weighted reflectors and a multi-strip coupler (MSC). In the structure, the width-weighted reflectors are to be responsible for the frequency response of the filter. The reflectors are optimally designed to realise the specified frequency response by taking account of the SAW reflectivity of width-weighted electrodes. The filter having 3 dB bandwidth of 4.0 MHz was designed at the centre frequency of 200 MHz and fabricated on 128° YX-LiNbO3. The total acoustic length of the filter was reduced to less than 5 mm. The experimental result obtained was in good agreement with the theoretical prediction
Keywords :
VHF filters; band-pass filters; frequency response; interdigital transducers; surface acoustic wave filters; 200 MHz; 4 MHz; IDT; LiNbO3; LiNbO3 substrate; SAW reflectivity; filter frequency response; miniaturised SAW filter; multi-strip coupler; surface acoustic wave filter; width-weighted electrodes; width-weighted reflectors; Acoustic devices; Bandwidth; Digital filters; Electrodes; Frequency response; Mobile communication; Reflectivity; Resonance; SAW filters; Surface waves;
Conference_Titel :
Frequency and Time Forum, 1999 and the IEEE International Frequency Control Symposium, 1999., Proceedings of the 1999 Joint Meeting of the European
Conference_Location :
Besancon
Print_ISBN :
0-7803-5400-1
DOI :
10.1109/FREQ.1999.841459
