Ultra-Wideband Wide-Angle Scanning Sparse Array Antenna Based on LPDA

A novel ultra-wideband wide-angle scanning sparse array antenna is proposed in this paper. The log periodic dipole antenna with exponential shape is selected as the unit of sparse array antenna due to its small size, ultra-wideband and non-frequency-dependent characteristics. After the unit design is completed, genetic algorithm is used to optimize the array layout efficiently, and the final number of units is determined to be 40. The aperture area of the sparse array is 300_mm x 300_mm. Compared to the conventional periodic array, the proposed sparse array has reduced about 190 antenna units. Through optimization of performance and position of the element, the sparse array can achieve active VSWR < 3 and S11 < -10dB in the ultra-wideband of 3 - 12GHz (120%). Simulation results show that the beam pointing accuracy is better than 10 degrees, the azimuth scanning angle is plus or minus 45 degrees, and the pitching scanning angle is plus or minus 30 degrees. The gain at the center frequency 7GHz is about 22dBi.