0.7-dB insertion loss at 60 GHz with a bandwidth of 50% and a return loss better than 15 dB from 43 to 73 GHz. The measured results corresponding to one transition can be determined from the back-to-back results. By accounting for the microstrip line and IWG losses based on separate measurements of transitions with different lengths, the insertion loss of one transition is calculated. The measured insertion losses of the IWG and microstrip feed line are 0.1 dB/mm and 0.3 dB, respectively. The extracted insertion loss per one transition is less than 0.1 dB over 43 to 73 GHz. This transition has relative robustness for a manufacturing accuracy within Ϯ0.1 mm.
CONCLUSIONA novel wideband microstrip line-to-IWG transition, suitable for compact integration of planar circuits and waveguide on the same substrate, has been proposed. The proposed transition has the features of low loss, broad bandwidth, and a simple structure, as compared with conventional IWG transitions. The insertion loss per one transition is less than 0.1 dB with a bandwidth of 50% at 60 GHz. This transition is usable for surface-mountable waveguide filters, ceramic packages, and hermetically sealed waveguide transitions at millimeter-wave frequencies.
ACKNOWLEDGMENTSThe authors acknowledge support of this work by Millisys, Inc. and OKI Electric Industry Co., Ltd. through the FAMN project.