A novel broadband antenna element for an S-band phased array demonstrator and the measurement of its active mutual coupling

The development of a novel antenna element which can be closely integrated with circuitry on a high permittivity substrate is described. The 2% to 3% loss due to backwards radiation could be eliminated, if necessary, and still leave adequate space for circuitry, by using triplate round the slot and with microstrip to triplate transitions each side. It may be possible to control element radiation patterns by shaping the dielectric interfaces and to improve the match by optimising the resonant layers, but in the absence of a rigorous theory this could be a long and expensive exercise. It is also possible that mutual coupling could be reduced by using elements with a circular aperture and arranging them on a triangular lattice