Micromachined High Gain Diagonal Horn Array Antenna With Suppressed Grating Lobes for 190 GHz-250 GHz

Abstract

This article presents a high gain, broadband silicon micromachined diagonal horn array antenna for the 190 to 250 GHz frequency band. The antenna array is configured to be built from 34 silicon layers. The upper 25 layers of silicon wafers create an 8 × 8 diagonal horn array antenna and the lower 9 layers form the feed network. The diagonal horn is selected as a radiation element for its 45° polarization direction, which suppresses side and grating lobes in the E-plane and H-plane after array formation. Polarization converters are innovatively employed in the feed network to resolve the issue of opposite polarization from waveguide T-junctions. In order to meet the silicon micromachining criteria, all diagonal horns and the feed network are step-profiled designed based on silicon wafer thickness. The 34 silicon layers are aligned and fixed by computer numerical control-milling metal tooling. Monte Carlo analysis is utilized to quantify the interlayer offset errors introduced during the assembly of the wafers. The measurement results are within the error allowance. The antenna achieves a peak gain of 30.9 dBi and a working frequency bandwidth of 27%. Characterized by highly directive radiation patterns with low side lobe levels in the E-plane and H-plane, the antenna is well-suited for next-generation THz point-to-point communication systems.