How Does it Work?

A plasma is an ionised gas which, when sufficiently dense, behaves as a conductor. A plasma antenna generates localised concentrations of plasma to form a plasma mirror which deflects an RF beam launched from a central feed located at the focus of the mirror. An ionised region, or solid state plasma, can be generated in silicon using electronically controlled devices (plasma diodes) that are positioned between closely spaced metalized surfaces which constrain the beam. The plasma can be freely moved by switching groups of plasma diodes on and off that follow the desired geometry of the reflector. The resulting pattern of plasma diodes forms a rosette of overlapping reflectors only one of which is active (i.e. reflecting) at any one time. This enables the beam to be steered quickly without the need for mechanical motion. In some realisations, the silicon disc (ie Si wafer) can act as a cylindrical lens, to form a lens/reflector system that enables the RF energy to be collimated.

Predicted Performance:

16 Beam Positions
Sidelobes < -16 dB
Gain = 14 dB
Switching Speed ~ 2 µ seconds
S11 < -15dB (5 to 6 GHz)

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