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CURATOR

Research Associate, Macquarie University

PINBOARD SUMMARY

To develop ground terminal antennas for providing high-quality internet via LEO satellites.

It is estimated that more than half of the world population, that about 4.2 billion people, do not have regular access to the internet. In the least developed countries, only one out of every ten people is online. Poor internet connectivity (insufficient speed or no connection at all) is a problem in remote regional areas of even the developed countries like US, Australia, and Canada. To address this global “digital divide” and to cater for future bandwidth demands, satellite internet is considered as a most feasible and optimal solution. This solution relies on a large number (hundreds) of low cost low earth orbit (LEO), i.e. non-geosynchronous, satellites. An essential part of the solution is a low-cost and high-performance steerable beam antenna for a ground terminal. Beam-steering is, therefore, imperative to realize global connectivity using futuristic satellite internet services. The current beam-steering antenna techniques can be broadly grouped into two types. The first type is to design a large antenna with a fixed beam and move the whole antenna to steer its beam in two angular dimensions. The second method is to design a two-dimensional antenna array with several hundreds or thousands of low-gain antennas, and steer its beam electronically using a large number of electronic devices. Both of the existing beam steering techniques cannot be a solution for realizing ‘global connectivity’ because they are either too bulky or too expensive. We have developed an innovative third method of beam steering, to fill the large gap between the two current methods mentioned above. Our method preserve the advantages of current mechanical methods (high efficiency and high power handling) without the limitation of bulkiness. At the same time this method is better than electronically-steered arrays because it is extremely efficient and does not suffer from issues associated with electronic devices such as non-linearity, distortion, heating and poor power handling. Our high-performance, low-profile steerable antenna concept has a planar base antenna and two specially designed metasurfaces. The metasurfaces are placed very close, within a fraction of a wavelength, to the antenna in its near field. Each of the metasurfaces comprises of spatially distributed phase shifting cells. With two independently rotating metasurfaces, antenna beam can be directed to any direction within a large cone.

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