Single Patch Antenna With Monopulse Patterns

A dual probe-fed single microstrip patch antenna for the monopulse tracking applications is proposed. The monopulse antenna, consisting of a slot-embedded patch, two symmetric probe feeds and a 180 degrees directional coupler is fabricated in a normal PCB process with a size of only 0.63 lambda x 0.69 lambda. The sum or difference patterns are achieved with out-of-phase or in-phase feeding mechanism. A prototype shows that the measured -10-dB impedance bandwidth is 345MHz (2.11GHz-2.455GHz), and the measured port-isolation is higher than 15dB at the frequency band 2.12GHz-2.50GHz. The measured sum gain and difference null at boresight are 7.54dBi and -32.7dBi, respectively.