A transition between NRD guide and microstrip line at 60 GHz

A transition between an NRD guide, suitable for construction of high performance millimeter-wave integrated circuits, and a microstrip line, being used to mount semiconductor devices such as HEMT, HBT, and MMIC, was developed at 60 GHz. Main emphasis was placed on a manner of field matching between the NRD guide and microstrip line. We proposed a new transition structure using a vertical strip line, having easy coupling performance to the NRD guide, and a coaxial line, being used to connect with the microstrip line. Moreover, we devised a new packaging structure of the microstrip line to prevent undesired leakage between the NRD guide and microstrip line. The insertion loss of the fabricated transition was measured to be less than 0.5 dB in the bandwidth of 3 GHz at a center frequency of 60.5 GHz. The transition was applied to MMIC amplifier integration in the NRD guide at 60 GHz. The forward and reverse gains were measured to be 15 dB and -20 dB, respectively, at 60 GHz.