Design of Ku-Band 2-D Monopulse Waveguide Slot Array Antenna

In this paper, a Ku-band 2-D monopulse waveguide slot array antenna is designed for sum-and-difference angle measurement. The array antenna consists of three main layers: the radiating layer, the coupling layer, and the feeding layer. A sum-and-difference network for the feeding of the waveguide slot array is proposed, which is composed of four 3-dB directional couplers connected end-to-end, with phase shifters externally attached. At the center frequency, the transmission amplitude at each port of the sum-and-difference network is distributed between -6.4 dB and -5.9 dB, which is close to the theoretical value of -6 dB. A high-gain, low-sidelobe waveguide slot array antenna is designed. Within the frequency band of 14.6 GHz to 15.4 GHz, the port reflection coefficient is less than -10 dB. The maximum gain at the center frequency is 29.6 dBi. The null depth is -34.1 dB for the elevation difference beam, and is -41.7dB for the azimuth difference beam.