Improvement in the electrical performance of dielectric space frame radomes by wire loading

One approach has involved the replacement of metal frames by dielectric frames composed of high modulus, glass-fibre-reinforced polyester (GRP). Despite this move, undesirable sidelobing has still been found to be present for certain types of antenna configuration. A possible solution to this problem involves impedance loading the GRP members with thin wires and an investigation into the feasibility of using this technique in a radome operating at around 1 GHz been reported. The previous work concentrated on reducing the scattering from the GRP radome struts alone since the dielectric membrane and strut star points should contribute little to the degradation of the antenna radiation pattern at these low frequencies. However, it was subsequently felt that due to limitations in the original theoretical struct model and measurement uncertainties, the original choice of loading configuration may not have been optimum. This contribution therefore examines in more detail the problem of impedance loading a dielectric space frame operating at a nominal frequency of 1 GHz, by scale modelling, at 10 GHz, in order to assess the optimum loading configuration for this frequency