12^th-Order 3-dB Quadrature Hybrid Coupler for Low Amplitude and Phase Imbalance in Extended W-Band Frequencies

A W-band quadrature hybrid couplers to achieve extended W-band is investigated, design, fabricated and measured. The goal is to achieve the passband beyond the standard 75-110 GHz passband, with amplitude imbalance less than 1.0dB. The simulated results indicate that for $12^{\mathbf{th}}$- order hybrid, the design of +− 1.0 dB amplitude imbalance can be achieved with 73 – 115 GHz passband, and the measured results shows that the 1-dB imbalance passband is 74 – 116 GHz. The measured phase error from 90 degree is less than +− 2 degrees over 67 – 116 GHz.