A Broadband and Low Sidelobe Monopulse Slot Antenna Array by Using Cavities and Multilayer Waveguide Feed-Networks

In this paper, a monopulse slot antenna array is designed to exhibit the performances of broad bandwidth and low side lobe. The antenna structure is consisted by corporate adjustment cavities and multilayer amplitude tapering feed-networks. Each adjustment cavity below the four radiation slots, which operates high radiation efficiency and great reflection suppression in a broad bandwidth. A multilayer amplitude-tapering feed-network with taylor synthesis is proposed for realize low side lobe characteristic. With detailed analysis, the prototype monopulse slot array antenna is presented with relative operation bandwidth is 15.6%, as well as the VSWR is less than 2.0. At center frequency, the gain of the sum beam is 32.4dB with the first side lobe is −23dB in E plane and −22dB in H plane respectively, as well as cross polarization is less than −40dB. Also, the depth of the difference beams in E-plane and H-plane are lower than −60dB and −50dB, respectively.