Broadband Waveguid-to-CPWG Transition With Butterfly-shaped Dipole

A broadband rectangular waveguide-to-coplanar waveguide with ground transition for large-chip-width substrate operating within terahertz frequencies (230-320GHz) is demonstrated in this work. This transition adopts a dipole antenna with butterfly-shaped coupling branches. This compact transition reduces parasitic effects by wire bonding and is suitable for direct integration with terahertz monolithic integrated circuits. The transition was designed based on a 50 μm thick InP technology and designed for standard waveguide (432×864 μm). The simulated results show that the bandwidth is as wide as 90 GHz, and the in-band return loss is better than 14 dB.