A Wideband Low-Profile Monopulse Feeder Based on Silicon Micromachining Technology for W-Band High-Resolution System

A wideband low-profile monopulse feeder at the W-band based on the silicon micromachining technology is investigated in this letter. The proposed monopulse feeder consists of four stepped horn elements as the radiating antenna array and four Magic-Tees as the comparator network for generating SUM and DIFF beams. In order to achieve the features of wide working bandwidth and low profile, a series of special structures are employed, such as a ridged structure and a metallic reduced-height waveguide, in Magic-Tees. The total thickness of this feeder is 2.65 mm (0.80λ), which includes six metallic layers. Then, the feeder is fabricated and experimented. This feeder has a working bandwidth of 21.7% (from 80.4 to 100 GHz) for ports 1 and 2, while a working bandwidth of 15% for port 3. More than 13.5 dBi is maintained for the gain of SUM patterns, and all gain ratios of SUM and DIFF beams are within 3.2 dB in the working bandwidth. The result indicates that this kind of feeder can be an excellent candidate for the W-band high-resolution system.