60GHz wideband Yagi-Uda antenna integrated on 2.5D through silicon interposer

This paper proposes a 60 GHz wideband Yagi-Uda antenna for 2.5 Through Silicon Interposer (TSI) platform. The integrated antenna comprises two parts: a wideband Marchand balun and a differential Yagi-Uda antenna. Marchand balun transfers the balanced signals to un-balanced ones, and subsequently used to feed the differential Yagi-Uda antenna. To achieve wideband, the discussed Marchand balun is realized with the strong broadside coupling between metal layers based on redistributed layer (RDL) technology. Its insertion loss is 3.8 dB, and 15 dB return loss band is from 52 GHz to 74.3 GHz. Phase deviation is consistent and 1-2⁰ from the ideal differential outputs. The proposed Yagi-Uda antenna constitutes a half-wavelength dipole as the antenna exciter; the ground plane of rear feeding network is inherently used as inductive reflector. In the front side, a 0.68-wavelength open-circuited stub functions not only as a capacitive director, but also introduces one more resonant mode to widen the antenna operating bandwidth. Lastly, impedance matching from exciter dipole and 100 Ω Marchand balun is realized by the co-planar strip (CPS) line. As a result, a wideband Yagi-Uda antenna on TSI platform with peak 4.7 dBi endfire radiation is successfully achieved, and its fractional bandwidth is 26.0% from 54 GHz to 70.2 GHz.