Cosecant-Squared Shaped Pattern Stability With Frequency in Series-Fed Antennas at mm-Waves

The frequency-dependent distortions in the beam peak direction and cosecant-squared shape are jointly analyzed for the first time in travelling-wave antennas. A novel center-fed proximity-coupled patch array at 26 GHz is proposed and compared with the edge-fed counterpart. The proposed center-fed array provides less than 1 degree beam squint, less than 1.5 dB variation in the realized gain and less than 20% root-mean-square error in the beam shape within a 700-MHz bandwidth.