Design of low sidelobe slotted waveguide monopulse antenna array

In this paper, a low sidelobe slotted waveguide monopulse antenna array working at Ka-band is proposed. The design procedure of radiating element parameter extraction and the synthesis of planar array is introduced. A 28 × 28 circular slotted waveguide antenna array is presented. The simulated bandwidth (return loss less than -20 dB) of antenna array is 1.48% and the corresponding isolations between the sum and difference ports are better than 45 dB. The sum beam standard gain difference is about 1.69 dB while the sidelobe levels are -29.64 dB in E-plane and -28.86 dB in H-plane. The gain differences between the sum channel and difference channels are around 3.6 dB and the null depths are below -50 dB in both planes.