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%.