A Scalable Differential Series-fed Dipole Array for D-band Radar in Wafer-Level Package Technology

This article presents the design and characterization of a scalable series-fed differential Antenna-in-Package (AiP) design, demonstrated as a four- and a six element reflector-backed linear dipole array that has been realized in a resin-based fan-out wafer-level package technology. The simulated four- and six-element designs achieve −10 dB input reflection bandwidths of 5.5 and 5.9 percent, realized gains of 14 and 15.4 dBi, and side-lobe levels of −10.7 and −12.1 dB, respectively. Frequency scanning is limited to ±4° throughout the bandwidth for both designs. The realized samples were characterized through probed measurements in a state-of-the-art millimeter-wave anechoic chamber. After taking into account the influence of the RF probe on antenna performance, the measurements corroborated the simulated results. The presented designs represent a beyond-state-of-the-art contribution in gain-to-area ratio to the currently limited number of high-gain differential AiPs at D-band found in literature. This article expands upon a 2025 EuCAP paper with more detailed descriptions, a scalability study, and a simulated feasibility demonstration of a scanning array implementation for further gain enhancement and a ±45° scan range.