A Compact and Broadband Waveguide-to-GCPW Transition for 260–400 GHz Large-Width TMIC

In this letter, a novel broadband transition from grounded coplanar waveguide to rectangular waveguide for large-width terahertz monolithic integrated circuit (TMIC) is proposed. This transition utilizes a dipole antenna with asymmetrical coupling probe to eliminate the additional parasitic effects caused by off-chip interconnect transition technology thereby achieving low-loss performance. In addition, periodic metal pins are utilized to address the resonances of large-width TMIC. Compared with traditional dipole transition, the proposed structure has enhanced the broadband coupling efficiency. Fabricated on 50-μm indium phosphide (InP) substrate, the back-to-back transition achieves a return loss of better than 12 dB with an average insertion loss of 4.72 dB across 272–400 GHz.