Improved Sidelobe Recognition Method Using Boresight Error in a Uniform Circular Array for Wideband Direction Finding System

• Published in: IEEE access Vol. 9; pp. 108062 - 108068
• Main Authors: Kong, Deok Kyu, Woo, Daewoong, Kim, Jaesik, Yoon, Young Joong
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Antenna arrays; Antennas; Array antenna; Blanking; Boresight error; Boresights; Broadband; Broadband antennas; circular array; Direction finding; Errors; interferometer; Interferometers; Microstrip antennas; Pattern recognition; Radar antennas; Recognition; Sensors; sidelobe recognition; Sidelobes; sum-delta monopulse; Wideband
• ISSN: 2169-3536; 2169-3536
• DOI: 10.1109/ACCESS.2021.3100647

A strong signal through the antenna sidelobes can be interpreted as a main lobe signal and may cause a major angle error in the direction finding system. An auxiliary antenna channel in the Maisel's sidelobe blanking system increases the cost, and the method using each boresight error (BSE) of the monopulse and interferometer causes many errors in the real antenna. In this paper, a sidelobe recognition method applicable to a wideband uniform circular array without auxiliary antenna channel is proposed. Four boresight errors are obtained from monopulse and interferometer in the circular array and then the maximum value of differences between boresight errors is taken and is compared to the optimal threshold value. The results have the effect of reducing errors occurring in the sidelobe region while maintaining the performance in the main lobe region. To validate the proposed method, a circular array antenna with eight wideband microstrip antennas is designed and manufactured. As a result, there is a significant improvement in the error rate compared to the existing method. It is confirmed that there is no error when the threshold value is from 0.5 ° to 0.7 ° at 6, 9, and 12 GHz, and the error rate is less than about 1 % when the threshold value is between 0.4 ° and 1.0 °.