Radial line slot array antenna with vertical waveguide feed for F‐band communication

The authors present concentrically arrayed radial line slot array antenna for operation at 106 GHz. For compact design, they propose a vertical waveguide feeding with a cross‐slot structure at the waveguide to cavity transition. Aperture design and optimisation are carried out using particle swarm optimisation with the goal to minimise the cross‐polarised radiation. Antenna prototypes were fabricated using a slotted plate with nickel and radial line cavity with copper. Fabricated aperture showed 72% peak radiation efficiency at 106.3 GHz with a gain bandwidth of 8.5% and 3‐dB axial ratio bandwidth of 18%.