Broadband monopulse microstrip antenna array for X‐band monopulse tracking

Abstract

In this study, a broadband planar multilayer monopulse antenna at the X‐band for monopulse tracking applications is presented. A monopulse comparator has been designed using four hybrid ratrace for feeding the radiating elements of the antenna. Each radiating part of the monopulse antenna consists of 4 × 4 electromagnetically coupled microstrip antenna array. To achieve circular geometry as well as better side‐lobe level (SLL), a hybrid feeding technique is used in radiating antenna array by adding a few elements in series at the end elements of the parasitic layer of a 4 × 4 corporate fed array. The prototype has been fabricated, tested and measured results are compared with simulated results. The simulated impedance bandwidth for | S 11 | ≤ −10 dB is 21% (8.6–10.6 GHz). A measured peak sum beam gain of 24.4 dBi has been obtained. Measured SLL of <−15 dB has been achieved in both elevation and azimuth planes along with a null depth of <−35 dB for difference patterns in both the planes. The radiation pattern is symmetrical in both the planes with half‐power beamwidth nearly equal to 9.0°.