Millimeter-Wave Elliptical Lens Antenna for Fan-Beam Monopulse Applications

A novel two-dimensional elliptical lens monopulse antenna at millimeter-wave frequencies is presented using the technique of dielectric-filled parallel plates where TE mode propagates. A cavity-backed aperture-coupled elliptical patch antenna array with sum/difference ports is located at the back of the elliptical lens as a feeding antenna. The lens antenna is designed, fabricated and tested at 35 GHz. Measurements show clean and symmetrical fan-beam patterns are realized for both the sum and the difference beams. The measured 3-dB - and -plane beamwidths of the sum pattern are 5.3° and 37°, respectively. A gain of 16.7 dBi is realized for the sum beam (86% radiation efficiency), while a deep null of -32.4 dB is achieved for the difference beam. In addition, a 10-dB impedance bandwidth of 7.1% is measured for both the sum and difference beams.