Broadband GaAs On-chip E-band Series Fed Antenna Arrays

This paper presents an E-band (70-90 GHz) series-fed antenna array designed for GaAs-based phased array systems. While the initial design was optimized for a thinned 200 µm substrate, the prototype was fabricated on a standardavailable 350 µm GaAs wafer to investigate the feasibility of using non-thinned substrates. Experimental results demonstrate that the impedance bandwidth (S11 < -10 dB) is remarkably stable across the 20 GHz span despite the increased substrate thickness. However, a reduction in realized gain was observed, which is analyzed in the context of surface wave excitation and dielectric loading. This work provides a critical performance baseline for E-band arrays integrated into thick-wafer packaging environments.