High gain, dual frequency, dual polarization, low profile antenna design for millimetre-wave communication systems

A design is given for a low profile, high gain antenna which transmits and receives at two different frequencies at two perpendicular polarizations. The antenna is composed of two arrays of traveling-wave slots positioned normal to one another and fed by a parallel-plate waveguide structure. The look angle of each array is determined by the ratio of the phase coefficients of the waveguide to that in air, β _g/β_o. In order to obtain the same look angle for both the transmit and receive beams, the parallel-plate waveguide is partially loaded with a dielectric to achieve the appropriate β_g/β_o ratios. The parallel-plate waveguide is fed by two horn-lens structures from opposite ends, folded beneath the radiating structure via two 180° bends. The calculated radiation patterns, beamwidths, squint angles, and mechanical tolerances are given for a typical Ka-band satellite terminal antenna design