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.
Unique attenuation characteristics of ku-band Lune-Q antenna for Satellite retransmission of terrestrial digital broadcasting signal
This paper deals with the unique low rain attenuation characteristics of the Lune-Q antenna, which is used in the satellite retransmission system for terrestrial digital broadcasting CTV signal by using the 14/12 GHz band transponder. To achieve the optimum design of the satellite retransmission system of terrestrial CTV signal, propagation experiments to determine the propagation characteristics and confirm the satellite digital broadcasting CTV transmissions service quality confirmation were carried out in 2006, between the JSAT Yokohama Satellite supervisory and control station (JSAT-ES) and Hokkaido Institute of Technology (HIT) earth-station (HIT-ES). During the propagation experiments, it was found that the Lune-Q antenna rain attenuation characteristics are superior to those of the conventional parabolic antenna, i.e., small rain attenuation values. The rain attenuation values of conventional parabolic antenna and the Lune-Q antenna were compared, for the period from April to October 2006. It can be observed that rain attenuation values of the Lune-Q antenna were about 1/10 times lower. The small rain attenuation characteristics are considered to originate due to reasons such as multi-path reception by the Lune-Q lens characteristics, the feed horn position, and polarization effects, etc.