Accession Number:

ADP013362

Title:

An S-Band Reflection-Type Phase Shifter - A Design Example Using Ferroelectrics

Descriptive Note:

Conference proceedings

Corporate Author:

GEORGIA INST OF TECH ATLANTA SCHOOL OFELECTRICAL AND COMPUTER ENGINEERING

Report Date:

2003-04-03

Pagination or Media Count:

6.0

Abstract:

One of the challenges faced in using ferroelectrics in high frequency devices is how to effectively use the material in a circuit design. A compact reflection-type phase shifter fabricated on sapphire substrates coated with ferroelectric barium strontium titanate BST thin films has been built which shows the promise of using BST thin films in the design of tunable microwave devices. The phase shifter, fabricated as one monolithic assembly, consists of a 3dB coupler, meandered line inductors and tunable interdigital capacitors. A continuously variable phase shift range of more than 100 deg using the branch-line coupler was obtained at a center frequency of 2.95 GHz, and more than 900 deg phase shift over 200 MHz bandwidth with a bias voltage range from 0 V to 175 V. The phase shifter using the Lange coupler has over 700 MHz bandwidth centered at 2.2 GHz with a phase shift of more than 90 deg and an insertion loss less than 2 dB and return loss of greater than 14 dB, over a bias voltage range from 0 V to 160 V. The loss of the BST phase shifter presented in this work is on the order of other commercially available RF front-end components, such as bandpass filters and RF switches. This holds promise for the practical realization of smart antenna systems in cellular handsets and wireless LAN cards.

Subject Categories:

  • Physical Chemistry
  • Electricity and Magnetism
  • Radiofrequency Wave Propagation

Distribution Statement:

APPROVED FOR PUBLIC RELEASE