Circumferentially conformal slot array antenna and its Ka-band multibeam applications

A standing-wave slot array covered with a two-layer dielectric slab based on substrate integrated waveguide (SIW) technology, which is circumferentially conformed to a cylinder, is designed, fabricated and measured at Ka-band. The radiating part consists of seven slotted cylindrical SIWs, each of which has four-element longitudinal slots. Several such slot arrays fed by Rotman lenses are grouped on a cylinder along the circumferential direction to cover a 2D field of view. The microstrip Rotman lens is employed as the beamforming network with seven input ports, which can generate a corresponding number of beams to cover −35° to 35° along 1D (E-plane). Another dimension (H-plane) is covered from −52° to 52° with four beams generated by the slot arrays group. A prototype antenna is fabricated, the measured results demonstrate its ability of scanning over a 2D field of view with multiple beams. This type of multibeam conformal antenna is a good candidate for high-speed vehicles or communication base stations requiring electronic beam-scanning capabilities and considering conformal reasons.