SAW filters with high stopband rejection based on a cascade connection of selective elements

Author

Bausk, Evgeniy V. ; Yakovkin, Igor B.

Author_Institution

Inst. of Semicond. Phys., Acad. of Sci., Novosibirsk, Russia

Volume

42

Issue

2

fYear

1995

fDate

3/1/1995 12:00:00 AM

Firstpage

159

Lastpage

163

Abstract

To achieve a high stopband rejection in surface acoustic wave (SAW) filters a construction that includes a cascade of some elements (interdigital transducers (IDT) and multistrip couplers (MSC)) is used. In this case each element has to maintain a comparatively low frequency selectivity, and this permits a simple model and a high-speed calculation process to be employed for its design. The proposed constructions have an apodized transducer with a metal coating instead of a passive electrode region as the input IDT and broadband withdrawal weighted unapodized transducer as the output IDT. One or two group-type multistrip couplers (MSC) provide an additional frequency selectivity. The original synthesis algorithms have been developed for design of IDT and MSC structure.<>

Keywords

cascade networks; frequency response; interdigital transducers; network synthesis; surface acoustic wave couplers; surface acoustic wave filters; SAW filters; apodized transducer; broadband withdrawal weighted unapodized transducer; cascade connection; filter design; high stopband rejection; high-speed calculation; interdigital transducers; low frequency selectivity; metal coating; model; multistrip couplers; synthesis algorithms; Acoustic transducers; Acoustic waves; Coatings; Couplers; Electrodes; Frequency; Passive filters; Reflection; SAW filters; Surface acoustic waves;

fLanguage

English

Journal_Title

Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on

Publisher

ieee

ISSN

0885-3010

Type

jour

DOI

10.1109/58.365228

Filename

365228