Wideband 2-D Monopulse Antenna Array With Higher-Order Mode Substrate Integrated Waveguide Feeding and 3-D Printed Packaging

Abstract

A wideband 2-D monopulse antenna array with compact integrated structure is presented. First, based on the slotline/coplanar waveguide (CPW) excitation, a substrate integrated waveguide (SIW) higher-order mode excitation technique is discussed, and a wideband 1-D monopulse antenna array with miniaturized feeding structure is proposed. Then, the designed 1-D array is further extended into a 2-D array. The whole 2-D array is divided into four subarrays to simplify the array feeding. Orthogonal CPW-to-microstrip transition is introduced to utilize the array vertical space and obtain compact feeding arrangement. A 2-D monopulse comparator with broadband accurate feeding amplitudes and phases is also designed to feed the array. Finally, by implementing 3-D printing technology, the array components are packaged as a whole structure, and flexible array arrangement with high integration level can be realized. With the proposed design method, a 2-D monopulse array covering the entire $X$ -band (8–12 GHz, 40% bandwidth) is designed and fabricated. Compact structure and broadband monopulse performance make the proposed array an attractive candidate for wideband accurate target detecting and tracking applications.