$W$ -Band Micromachined Antipodal Vivaldi Antenna Using SIW and CPW Structures

A novel W-band (75-110 GHz) surface micromachined Vivaldi antenna fed with a new combination of coplanar waveguide and substrate-integrated waveguide is proposed. The design procedure of the feeding structure and the effects of the antenna's key structural features on its return loss and gain are studied in detail. The selected exponential taper with optimized feeding parameters results in a significantly higher gain (gain > 10 dBi) compared to similar tapered slot antennas reported in the literature over the entire bandwidth of operation. The antenna is fabricated using microfabrication processes, and high correlations between simulation and measurement results confirm its low-loss performance and symmetric and stable radiation pattern over the entire frequency range of 75-110 GHz.