Mesh antennas for dual polarization

Three mesh antennas, all having an extremely small antenna height of approx imately 0.06 wavelength above a ground plane, are presented. First, a mesh antenna excited with a balanced feed is analyzed. It is revealed that the m esh antenna radiates a linearly polarized wave with no cross-polarization c omponent in the principal planes. The radiation mechanism is explained usin g the current distribution, Second, a mesh antenna excited with an unbalanc ed feed is analyzed. This antenna shows almost the same radiation character istics as the mesh antenna with a balanced feed. The frequency bandwidth fo r a VSWR = 2 criterion is evaluated to be approximately 3%, Third, a mesh a ntenna having two perturbation elements is analyzed,It is found that the an tenna acts as a radiation element of circular polarization, The frequency b andwidth for a 3-dB axial ratio criterion is calculated to be approximately 1%. The mesh antennas in the first and second analyses can be used as dual linear polarization elements by appropriately switching the feed. Similarl y, the mesh antenna in the third analysis can be used as a dual circular po larization element by switching the feed.