Wideband tapered antipodal fin-line waveguide-to-microstrip transition for E-band applications

In this paper design of a wideband low loss tapered antipodal fin-line waveguide-to-microstrip transition operating in the 63-90 GHz frequency band is presented. The transition structure consists of a metal body containing a standard WR12 waveguide and a printed circuit board (PCB) with tapered antipodal fin-line fabricated using standard high frequency PCB technology Rogers RO4003C. The transition is realized by clamping the PCB between two halves of the metal body. All parameters of the designed transition are optimized for superior performance in the 71-86 GHz band that is dedicated for backhaul systems of mobile networks. Measurement results of the designed waveguide-to-microstrip transition show that it provides a large transmission bandwidth of 63-90 GHz (> 27 GHz) for the 10 dB level of return loss. The measured average insertion loss is about 0.6 dB in the 71-86 GHz frequency band and is lower than 1.1 dB in all the E-band from 60 GHz to 90 GHz. Hence, the achieved characteristics are sufficient for use the designed transition in various E-band applications such as WLAN/WPAN communications, 71-76/81-86 GHz wireless backhaul systems, and 77 GHz automotive radars.