A D-Band Micromachined End-Fire Antenna in 130-nm SiGe BiCMOS Technology

The design of a radiation-efficient D-band end-fire on-chip antenna utilizing a localized back-side etching (LBE) technique, as well as an antenna-in-package (AiP) on a low-cost organic substrate, is presented. Quasi-Yagi-Uda antennas are chosen for end-fire radiation because of their compact size. The on-chip antenna is realized in the back-end of the line (BEOL) process of a 130-nm SiGe BiCMOS technology, whereas the in-package antenna is realized in liquid crystal polymer (LCP) technology for comparison. The on-chip antenna design is optimized to meet both process reliability specifications and radiation performance, and corresponding design guidelines are provided. The fabricated on-chip antennas show the state-of-the-art performance with a peak gain of 4.7 dBi, simulated radiation efficiency of 82%, and measured radiation efficiency of 72%-76% using the gain/directivity (G/D) and wheeler-cap methods at 143 GHz. The antenna demonstrates a 3-dB gain bandwidth of more than 30 GHz and 10-dB impedance bandwidth greater than 20 GHz (14% impedance bandwidth). The measurements of the on-package end-fire antenna showed very comparable results with a peak measured gain of 6 dBi and a simulated and measured radiation efficiency of 92% and 86% at 143 GHz. These results demonstrate that highly efficient on-chip end-fire antenna implementation is possible in standard commercially available BiCMOS process.