A Wide-Band Aerial System for Circularly Polarized Waves, suitable for Ionospheric Research

An aerial system is described which is capable, without readjustment, of selecting one or other, of two circularly polarized waves of opposite sense over a frequency range of 2¿6 Mc/s when they are incident vertically upon the system. Two horizontal dipoles are used at right angles and are associated with two corresponding inductance-capacitance lattice networks. E.M.F.´S in the aerials, which are initially 90° out of phase, may be added in phase, thus giving selection of a circularly polarized component. A discrimination ratio between the components of at least 12:1 has been obtained for frequencies from 2 to 6 Mc/s.