Ultra-Wideband Planar Dipole Array Antenna for Multifunction Phased Array Radars

In the study, an ultra-wideband array antenna for multifunction phased array radars (MPAR) is proposed. Due to the low-profile and ultra-wideband characteristics, the planar dipole elements are utilized to form an array antenna. Their performances are enhanced by using an optimized microstrip-sector feeding structure. The array antenna is a combination of subarrays, each of which corresponds to 4 x 4 transmit/receive channels. Four subarrays are fabricated in a standard printed circuit board (PCB) process to investigate the planar dipole array antenna theoretically and experimentally. Both simulated and measured results show that the proposed array antenna achieves 87.0% impedance bandwidth (VSWR < 2.0 in the normal direction) from 1.3GHz to 3.3GHz, according to the specific requirements of an MPAR project. The active VSWR is less than 2.0 and 3.0 while the scan angle is -30 degrees similar to 30 degrees and -45 degrees similar to 45 degrees, respectively. It means that this array antenna has wide-scan capability. In general, the balanced optimization between the electrical and mechanical performances makes the proposed array antenna attractive for MPARs and other compact systems.