Abstract: This paper researched the waveguide-to-microstrip antipodal finline transition at W band, analyzed and simulated antipodal finline transition of Cosine-squared taper function curve and flexible spline curve, designed and fabricated an spline curve antipodal finline transition of backtoback structure. The measured results show that the insertion loss is less than 1.3dB, and the return loss is less than -13dB in whole W band, the insertion loss of a single transition is less than 1.0dB, and the return loss is less than -20dB in (90~99)GHz, achieve good performance.

Key words: W Band, Waveguide to microstrip, ⁺Antipodal finline