SIW Pillbox Antenna for Monopulse Radar Applications.

A multibeam pillbox antenna system incorporating monopulse phase comparison technique is proposed in the 24-GHz band. This low-profile antenna architecture combines the scanning capabilities of pillbox configurations and enhanced resolution of two-quadrant monopulse technique; this approach avoids mechanical orientation of the antenna system for tracking applications. The radiating panel consists of two subarrays of 23 slotted waveguides, with 8 slots per waveguide. The beam is scanned in E-plane over a field of view of \pm \bf 40^\circ , and sum/difference patterns are generated in H-plane. Around the design frequency, \bf f = \bf 24.\bf 15\,\bf GHz, the antenna gain varies between 25 and 21.5 dBi for the central and extreme beams, respectively. The measured null depth is better than - \bf 16\;\textdB for all difference beam patterns. The antenna bandwidth for \bf VSWR < \bf 2 (\textbfS\textbf{ii} < - {\bf 10}\;\textbf{dB}) and isolation better than \bf 10\;\bf dB (\textbfS\textbf{ij} < - {\bf 10}\,\textbf{dB}) is equal to 4.5%. [ABSTRACT FROM PUBLISHER]