Performance of a 2-layer radial hole effective media lens
The outer polyethylene layer of a 8λ0 radius 2-layer polyethylene/cross-linked polystyrene lens was implemented as a radial hole effective media that allows the entire lens to be milled from a single billet of cross-linked polystyrene, simplifying construction by avoiding layer fitting problems. Full wave simulations in a commercially available simulator showed that increasing the number of radial holes to 3000 gave peak directivity within 0.3dB of the original cross-linked polystyrene/polyethylene lens. Both Particle Swarm Optimization and icosahedron based methods were trialed for distributing the holes evenly over the sphere. The latter method produced symmetrical meshes allowing symmetry planes to be used to minimize computational burden, but was bound to the numbers of holes produced by successive triangular face subdivision iterations.
Scalar feeds for 8 wavelength diameter homogeneous lenses
Improving the connectedness of airliners in flight to allow the realisation of passengers' expectations for uninterrupted cell phone usage and internet access requires overcoming the bottleneck between the airliners' internal networks and the wider world in a cost effective manner while still providing sufficient bandwidth. The 43.5 – 47GHz band is attractive for airliner to ground links due to lack of utilisation and the small physical size of high gain antennas. Consequently, NICT plans to conduct a demonstration of such a system in late 2009.
Directive Gain of Circular Taylor Patterns
The directive gain of circular Taylor patterns is determined. It is shown that so-called optimum patterns, i.e., uniform sidelobes in all planes, are severely limited for planar apertures because of excessive sidelobe power. The optimum directive gain of the circular Taylor pattern with a given sidelobe level can be obtained by appropriate design.