Accession Number:

ADA031421

Title:

Varactor-Tuned Helical Resonators at UHF,

Descriptive Note:

Corporate Author:

ROME AIR DEVELOPMENT CENTER GRIFFISS AFB N Y

Report Date:

1976-05-01

Pagination or Media Count:

31.0

Abstract:

A JTIDS requirement calls for narrowing the front-end bandwidth of fast-tuning L-band receivers in order to improve their interference resistance. Filters suitable for this application have to be of high Q and compact design. Frequency tuning or switching within microseconds is required. The performance of optimally designed halfwave helical resonators is investigated with microwave varactors of Q greater than 4000 and Q greater than 10000 at 50 MHz and 4V reverse bias as tuning elements. Four filters were designed to cover sections of a frequency range 294 MHz to 1256 MHz. At the low end of this range the varactor Q is comparable to or better than that obtained from helical resonators of 1-in. shield diameter. At the high end of this range the varactor Q is such that there is a substantial degradation of overall resonator Q at maximum varactor capacitance at 1V reverse bias. The compatibility of varactor-tuned helical filters with requirements of the JTIDS receivers is evaluated. Author

Subject Categories:

  • Electrical and Electronic Equipment
  • Countermeasures

Distribution Statement:

APPROVED FOR PUBLIC RELEASE