Mechanically Steered Lens Antennas for 45GHz High Datarate Airliner-Ground Link
ABSTRACT A mechanically steered hemispherical lens antenna was investigated using the commercially available MOM software FEKOTM to meet a requirement for a low weight and low cost mm-wave transmit antenna for installation onboard a large passenger aircraft. Hemispherical homogeneous lenses of relative permittivity 2.5 and 4 wavelength radius were found to meet the 26.5 dBic gain specification across 75deg elevation scan range. Distorting the circular reflecting plate under the hemispherical lens to an elliptical shape was found to increase the elevation scan range to 105deg, satisfying the scan requirement. Similar results were obtained with a relative permittivity 1.7 lens, when fed by a near field focused horn antenna. The advantage of the latter design is 40% reduction in mass of the lens.
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ABSTRACT: A two-layer hemispherical lens is reported which, combined with a ground plane, comprises the focusing aperture in a multi-beam scanning antenna. The 61 cm diameter lens was fabricated from polyethylene and polystyrene dielectrics. The finite ground plane introduces a scanning loss since its truncation effectively reduces the aperture area: the effect becomes significant at low elevation angles. This scanning loss was investigated from a theory for the aperture plane distribution; measurements with the lens; and numerical modeling using the commercial solver FEKO. The lens gain is 35.5 dBi at 11.5 GHz, equivalent to a dish of similar area.Antennas and Propagation, 2009. EuCAP 2009. 3rd European Conference on; 04/2009
Conference Paper: Scalar feeds for 8 wavelength diameter homogeneous lenses[Show abstract] [Hide abstract]
ABSTRACT: 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 - 47 GHz band is attractive for airliner to ground links due to lack of utilisation and the small physical size of high gain antennas.Prior work on this lens reflector topology produced two satisfactory designs; a epsiv<sub>r</sub>=2.5 lens fed by a conventional choked feed and a epsiv<sub>r</sub>=1.7 lens fed by a conical horn with dielectric insert. The latter gave superior cross-track plane scan performance with more stable 3dB beamwidth, but the dielectric insert would be prohibitively small and expensive to construct for the 43.5 to 47GHz band. An alternative higher gain scalar feed is thus required for the epsiv<sub>r</sub>=l .7 lens.Antennas and Propagation Society International Symposium, 2009. APSURSI '09. IEEE; 07/2009
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ABSTRACT: A lens-reflector antenna comprises a hemispherical dielectric lens with a planar reflector. Beam scanning may be achieved by moving a primary feed around the fixed lens or by rotating the lens reflector with respect to a fixed feed. Truncation of the reflector and obstruction of the aperture by mechanical supports introduce scanning loss. These effects are analysed through a numerical technique where the spherical wave expansion method is used to populate an effective aperture matrix in the near field, which is then modified to account for shadowing effects. The results are verified by a measurement campaign using a scale model and by comparison with the commercial EM solver FEKO.IET Microwaves Antennas & Propagation 08/2010; 4(7-4):828 - 836. DOI:10.1049/iet-map.2009.0283 · 0.97 Impact Factor