A <i>W</i>-Band Low-Loss Planar MMICs to RWG Transition Using Copper Additive Manufacturing and Its 1-D Phased Array Antenna-in-Package Application

This article introduces a novel integration approach for W-band 1-D scanning phased array systems, focusing on efficient transition structures and antenna integration. Utilizing copper additive manufacturing (AM) technology, the proposed transitions exhibit low loss and compact size, enabling the seamless integration of ridge waveguide (RWG) slot antennas with RF MMICs. The W-band transition offers a wide impedance bandwidth ranging from 85 to 105 GHz, with a reflection coefficient below -13 dB and an insertion loss (IL) of less than 0.3 dB. At 94 GHz, the transversal profile of the antenna is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.45\lambda _{0}$ </tex-math></inline-formula>, facilitating 1-D scanning up to ±60° and enhancing its suitability for W-band 1-D phased array applications. With a transition structure size of merely <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.4\times 3.43$ </tex-math></inline-formula> mm2, this approach demonstrates substantial potential for W-band RF front-end integration.