ANTENTOP- 03- 2003, # 004

Tunable Plasma Frequency Selective Surfaces for Shielding Radar Systems

This theoretical plot is of the plasma FSS array illustrated above. Each dipole element is assumed

to be in length, in diameter. The vertical separation

Schematic representation of an FSS dipole array

is taken to be while the lateral separation is taken to be The plot has the curves for the perfectly conducting case (high plasma frequency and

density) along with those for several values of the plasma frequency, which depends on plasma density. A well-defined reflectivity resonance exists at 1GHz. This result indicates that appreciable reflection occurs only for plasma frequencies above 2.5GHz. The results illustrate the essence of the plasma FSS: a highly reflective band stop filter can be achieved which can be switched on and off simply by controlling the properties of the plasma.

-Navy Phase I SBIR Contract N00178-03-C-1013 January 2003 - This contract intends to develop a

This sketch illustrates a finite section of an FSS dipole array. The array elements are the vertically aligned rectangular regions. The horizontal lines on the rectangles indicate the way in which the elements are broken up into segments for the purpose of defining current modes.

gas plasma antenna array architecture capable of meeting the broad Navy objectives for future shipboard radar systems. We are proposing a compendium of plasma technologies that could be integrated into existing radar suites or be designed into future revolutionary radars. These technologies

are plasma windowing, plasma waveguides, plasma

Plot of ASI's theoretical model

Frequency Selective Surfaces and flat parabolic arrays (FLAPS).

ASI Technology Corporation developed under contract with General Dynamics Electric Boat Division and in conjunction with the Plasma Physics Laboratory at the University of Tennessee, an inflatable plasma antenna. This antenna operatedat 2.4 Ghz and was designed to mount on the mast of an attack submarine. We have also demonstrated prototype plasma waveguides and plasma reflectors to General Dynamics.

Plasma Waveguide with energized tube as a switch acting as a window for a pulse

The following discussion illustrates why there is military and government support for plasma antenna concepts. The gas plasma antenna conducts electron current like a metal and hence can be made into an antenna but with distinct advantages. The following technological concepts are important to plasma antennas:

http://www.antentop.org/

Page 28