75–500 MHz quadruple-ridged horn antenna with dual polarisation

A dual-polarised, quadruple-ridged horn antenna with a coaxial feed operating over the frequency range of 75-500 MHz is presented. For the reduction of the antenna weight, a composite sandwich structure is used to build the antenna, which comprises solid aluminium and honeycomb materials. An adjustable shorting plate is put at the bottom of the antenna to prevent the occurrence of singularities created by standing waves. A Teflon plate is put at the centre position among the four symmetry ridges to mechanically support the huge antenna structure without breaking the symmetry of the ridges, leading to good electrical performance. Simulation and measured results are presented.