15-10-2010, 11:15 AM
PLASMA ANTENA.ppt (Size: 2.93 MB / Downloads: 849)
This article is presented by:
SHAJID TS
MODEL POLYTECHNIC COLLEGE VADAKARA
DEPT : APPLIED ELECT RONICS
Plasma antenna
INTRODUCTION
WHAT IS PLASMA ?
On earth we live upon an island of "ordinary" matter. The different states of matter generally found on earth are solid, liquid, and gas. Sir William Crookes, an English physicist identified a fourth state of matter, now called plasma, in 1879.
Plasma is by far the most common form of matter.
Plasma in the stars and in the tenuous space between them makes up over 99% of the visible universe and perhaps most of that which is not visible.
Important to ASI's technology, plasmas are conductive assemblies of charged and neutral particles and fields that exhibit collective effects. Plasmas carry electrical currents and generate magnetic fields.
PLASMA ANTENNA TECHNOLOGY
Plasma antenna technology employs ionized gas enclosed in a tube (or other enclosure) as the conducting element of an antenna. This is a fundamental change from traditional antenna design that generally employs solid metal wires as the conducting element.
Ionized gas is an efficient conducting element with a number of important advantages. Since the gas is ionized only for the time of transmission or reception," ringing" and associated effects of solid wire antenna design are eliminated.
The design allows for extremely short pulses, important to many forms of digital communication and radars.
UNIQUE FEATURE OF PLASMA ANTENNA
One fundamental distinguishing feature of a plasma antenna is that the gas ionizing process can manipulate resistance.
A second fundamental distinguishing feature is that after sending a pulse the plasma antenna can be deionized, eliminating the ringing associated with traditional metal elements. Ringing and the associated noise of a metal antenna can severely limit capabilities in high frequency short pulse transmissions.