D-Band Integrated and Miniaturized Quasi-Yagi Antenna Array in Glass Interposer

An integrated and miniaturized D-band quasi-Yagi antenna in glass interposer is presented. Single element, 1 × 2 and 1 × 4 test coupons are fabricated on 100- $\mu$ m glass substrate with low-loss polymer buildup films and the return loss, gain, and radiation pattern of the antennas are characterized. The proposed antenna utilizes a monopole radiator to achieve a higher bandwidth. Advantages of the glass substrate for beyond 5G communications in terms of enabling fine features and compact integration of other active and passive devices through chip embedding is discussed. An analysis of the substrate modes to ensure proper mode propagation in the selected stack-up is presented. Furthermore, the article discusses the challenges in planar antenna measurements in subTHz frequencies and it presents two measurement setups to overcome these challenges. The first is a low-cost probe station-based measurement setup to characterize the return loss and boresight gain, and the second is a diode-detector-based setup to measure the normalized radiation pattern. The proposed antennas achieve high bandwidth covering the frequency range of 110–170 GHz, and 4.78 dBi, 8.41 dBi, and 11.04 dBi gain for the single element, 1 × 2, and 1 × 4 array, respectively.