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Design of Ultra-wideband Array Antenna Based on Tightly Coupled Technology
Huifeng Sun and Minyuan Yu
Based on the shortcomings of the current ultra wide band (UWB) array antenna research and the engineering requirements, a tightly-coupled UWB array antenna is designed. The antenna uses a tightly-coupled dipole array (TCDA) as the antenna radiator and is fed by Marchand Balun with gradual impedance. It has the characteristics of dual polarization, low profile and high gain. The antenna also uses a double-layer frequency selective surface (FSS) and a cross-shaped resistive absorbing material to improve the wide-angle scanning performance, especially the self-excited oscillation caused by the short circuit zero points at high frequency. Through the simulation analysis of the antenna by HFSS, it is concluded that the array has VSWR < 3 in the range of 2-18 GHz. The VSWR is less than 3.5 in the range of 40° angle scanning on the H plane and the VSWR is less than 3.3 in the range of 85° scanning on the E plane, which has excellent E plane scanning capability. The profile of antenna array is 15mm (0.1 λlow), the polarization isolation is better than – 25dB, and the gain of 20×20 antenna array exceeds 20 dB, which can be used in airborne radar, space-borne radar and other application scenarios.
Keywords: tightly coupled antenna; ultra wide band antenna; dual-polarized; low profile