Accession Number:

ADA052703

Title:

Low Sidelobe SAW Filters Using Overlap and Withdrawal Weighted Transducers,

Descriptive Note:

Corporate Author:

ROME AIR DEVELOPMENT CENTER HANSCOM AFB MASS DEPUTY FOR ELECTRONIC TECHNOLOGY

Report Date:

1978-03-28

Pagination or Media Count:

8.0

Abstract:

In order to avoid frequency spurious signals in bandpass filtering applications, low out-of-band sidelobes are necessary. The purpose of the present paper is to describe in detail the techniques necessary to achieve 60-70 dB sidelobe SAW filters operating in the UHF Region. These techniques include the use of withdrawal weighted WW transducers either as both input and output of the filter or in combination with overlap apodized transducers plus a thorough understanding and control of second order effects. The utility of these procedures will be illustrated by a description of the design, fabrication and testing of a 335 MHz, 0.34 percent bandwidth, 15 dB insertion loss, SAW filter on ST quartz having sidelobes and all other spurious electromagnetic feedthru and bulk mode interference at least 63 dB below the output. In addition, experimental examples of design parameter variations and second order effects will be presented and correlated with theory where appropriate.

Subject Categories:

  • Acoustics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE