An ultra-wideband 3 x 3 Butler matrix with unique Vivaldi array structure for high-range resolution radars


Karamzadeh S., Rafiei V., Kartal M.

INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, 2022 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Publication Date: 2022
  • Doi Number: 10.1002/mmce.23086
  • Title of Journal : INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING
  • Keywords: 3 x 3 Butler matrix, beam-steering, low isolation, multilayer array, Vivaldi antenna, wide coverage antenna, ANTENNA, COMPACT, DESIGN, COUPLERS, PHASE

Abstract

Steerable antenna beam capability is an outstanding expectation for the development of automatic tracking systems and target detection. A switched beam array antenna, which can generate multiple fixed beams with enhanced sensitivity, emerges as a solution for beamforming tracking. On the other hand, it is known that the target can be detected with high-range resolution thanks to ultra-wideband (UWB) systems. In this work, a compact switched beam Vivaldi array antenna based on a Butler matrix for a UWB application capable of target detection with accurate target tracking is presented to meet the high gain and low side lobe level requirements. Based on a three-element antenna array, two methods have been applied to obtain small grating lobes and it has been shown that significant improvements can be achieved. Designed with a 3 x 3 UWB Butler matrix, the UWB array antenna can direct its beams in three directions in a direction range from -42 to 42 degrees. The measured result showed that the group delay was less than about 4.5 ns with variation of less than +/- 0.7 ns over the entire operating frequency band.