A Cost-Effective W-Band Antenna-in-Package Using IPD and PCB Technologies

This article presents a cost-effective millimeter-wave (W-band) cavity-backed slot antenna-in-package (AiP) built using commercially available integrated passive device (IPD), printed circuit board (PCB), and flip-chip assembly technologies. An IPD-PCB resonant cavity is formed by flipping an IPD chip on a PCB substrate with surrounding solder bumps to provide radiation through a square slot, which is patterned on one of the IPD metal layers. Moreover, a substrate-integrated waveguide (SIW) cavity under the IPD-PCB cavity and a wideband-grounded coplanar waveguide (GCPW) are built in the PCB substrate for the transition between a radio frequency front-end (RFFE) and the IPD-PCB cavity. The fabricated AiP achieves a 3.75-dBi gain at 94.5 GHz (TE
₂₁₀
mode) and a 10-dB impedance bandwidth of 1.9 GHz with a 3.61 mm
²
IPD chip area.