Abstract: A quadrifilar helix antenna used to transmit and receive wireless signals may include a number of inductively loaded antenna elements. The antenna elements may be helically wound around a cylindrical structure.

Abstract: A geodesic sphere phased array antenna system, capable of scanning the entire omni-directional communication space and comprising substantially equilateral triangular planar subarrays of antenna elements arranged in a geodesic sphere configuration. Icosahedron, one of the five regular solids and truncated icosahedron, one of the fifteen semi-regular solids are the preferred basis of the geodesic sphere phased array construction. The entire communication space is considered as subdivided into a large number of smaller cells and corresponding to each such cellular communication space, a contiguous set of the subarrays is energized and electronically phased to scan the cellular space.

Abstract: A microstrip antenna for radiating circularly polarized electromagnetic waves comprising a cluster array (20) of at least four microstrip radiator elements (22a-22d), each of which is provided with dual orthogonal coplanar feeds in phase quadrature relation achieved by connection to an asymmetric T-junction power divider (30) impedance notched at resonance. The dual fed circularly polarized reference element is positioned with its axis at a 45.degree. angle with respect to the unit cell axis. The other three dual fed elements in the unit cell are positioned and fed with a coplanar feed structure with sequential rotation and phasing to enhance the axial ratio and impedance matching performance over a wide bandwidth. The centers of the radiator elements are disposed at the corners of a square with each side of a length d in the range of 0.7 to 0.