A PRS-Less Resonant Cavity Antenna With Suppressed Sidelobe and Compact Size

Reducing size and side lobe level (SLL) is essential for resonant cavity (RC) type antenna. This paper proposes a PRS-less RC antenna with compact size, low profile and sidelobes. It is the first attempt to apply a hybrid cavity with a dielectric slab and a shaped ground with power manipulation (SGPM) function. Different from traditional un-equal power dividers utilized in array, herein, we proposed the SGPM to manipulate power distribution on the radiation aperture of a RC antenna. In addition, due to the utilization of the dielectric slab, intrinsic partially reflection can be occurred at the aperture interface between the dielectric and air. This achieves RC response while eliminating the usage of a separate partially reflective surface (PRS), which is often independently required in a conventional RC antenna. For validation, a prototype using the proposed design method is fabricated and measured. Its profile is 0.25 λ0. The SLL of the design is less than 18 dB across the operating band. Its peak aperture efficiency can reach to 69.1%. The overlapped operating bandwidth exceeds 13%. Compared to other RC antennas, the proposed design has characteristics of miniaturization, wideband, PRS-less, low SLL and low-profile.