A High Efficiency Slot Array Antenna Based on 2×3 Subarray

A high efficiency X-band monopulse slot array antenna based on a 2×3 elements subarray is designed and analyzed in this letter. The bottom layer of the antenna structure is a waveguide feed network for power distribution. The waveguide feed network transfers energy to the cavity array through coupling slots. Then, each cavity excites a 2×3 radiation slots array at the top layer. The subarray unit is used to form a larger array, providing flexibility in the size of the array antenna. Based on the 2×3 subarray, a 4×6 array antenna is designed and fabricated. At the center frequency in the X-band (8 GHz-10.4 GHz), the antenna achieves a gain of 21.5 dBi, a bandwidth of 26.1%, and a reflection coefficient below -10 dB. The measured efficiency of the array antenna exceeds 80% within the frequency band.