Dual-polarized fixed-beam high-gain array antenna for microwave and mm-wave applications

Abstract

There is a long-standing need for low-profile antennas with fixed-direction high gain in both polarizations. The design challenge for such an an array is that the elements and feed should be low loss and low cost. A new design using crossed slot elements for such a broadside fixed array is presented. The structure comprises an array of sub-arrays of slot elements with waveguide feeding. The design has excellent radiation properties (gain, pattern shape, polarization purity, bandwidth) and is suitable for microwave and millimeter-wave frequencies. An example design is presented that has a gain of 12 dBi, aperture efficiency of 54%, and a polarization isolation of 40 dB, all over a bandwidth close to 10%. An advantage of this structure is its scalability to increase its size and provide higher gain without major modifications and without increasing the loss significantly — a major advantage of waveguide-fed slot arrays. For example, the radiation efficiency of a 4×4 array using aluminum is ∼99% from simulation.