29-06-2010, 06:24 PM
Development of microwave devices tasks some new problems in the antenna systems theory and practice. Decreasing dimensions and weight of the radiating elements keeps to be the traditional and current question. In the making of power and superpower pulse sources the wide band of the work frequencies (from tens MHz to tens GHz) achievement is a current question too. Pulse power levels obtained now in such sources have the units of GW values. That power is determined by high values of the antenna input voltage (units of megavolts). It can leads to breakdowns in the feeder and antenna. Such a problem also arise in the making of mobile sources that have power of tens megawatt value. When such sources are made on the magnetic cumulative generator (MCG) [1] base the task of decreasing of dimensions and weight of them keeps to be relevant. MCG operation principle is grounded on transformation of explosive material potential energy into electromagnetic energy. The output voltage in such generators exceeds 30KV value under there volume in 0.5l and mass in 300g values. It is clearly that practical realization of such a source requires making unconventional decisions in the developing both feeder and antenna. One of the possible ways of the problems decision is the plasma antenna application.
In recent years, the rapid growth in both communications and radar systems has led to a concomitant growth in the possible applications and requirements of antennas. These new requirements include compactness and conformality, rapid reconfigurability for directionality and frequency agility and for military applications should also allow low absolute or out-of-band radar cross-section and facilitate low probability of intercept communications. Investigations have recently begun on the use of ionised gases or plasmas as the conducting medium in antennas that could satisfy these requirements. Such plasma antennas may even offer a viable alternative to metal in existing applications when overall technical requirements are considered. . Possibilities of the plasma application for antenna parameters control have been proposed in the sixties of 20 century. In work the test data of 10Ghz signal transmission are presented. The transmission was realized along a plasma channel that was created by the atmosphere breakdown. The atmosphere breakdown was created by the focused laser emission. Only a few works are known, for example , that carries results of calculations of electromagnetic field reflected by surface girded by plasma layer. It was experimental shown that an interaction of the magnetized plasma and the shortcut dipole girded by the plasma leads to increasing of the signal power emitted into a free space . But there is insufficient quantity of the works dedicated to development of the plasma antennas designed for work in the terrestrial atmosphere conditions. Methodical researches in that area have not done yet. This work object is to fill in a varying degree that vacuum.
In recent years, the rapid growth in both communications and radar systems has led to a concomitant growth in the possible applications and requirements of antennas. These new requirements include compactness and conformality, rapid reconfigurability for directionality and frequency agility and for military applications should also allow low absolute or out-of-band radar cross-section and facilitate low probability of intercept communications. Investigations have recently begun on the use of ionised gases or plasmas as the conducting medium in antennas that could satisfy these requirements. Such plasma antennas may even offer a viable alternative to metal in existing applications when overall technical requirements are considered. . Possibilities of the plasma application for antenna parameters control have been proposed in the sixties of 20 century. In work the test data of 10Ghz signal transmission are presented. The transmission was realized along a plasma channel that was created by the atmosphere breakdown. The atmosphere breakdown was created by the focused laser emission. Only a few works are known, for example , that carries results of calculations of electromagnetic field reflected by surface girded by plasma layer. It was experimental shown that an interaction of the magnetized plasma and the shortcut dipole girded by the plasma leads to increasing of the signal power emitted into a free space . But there is insufficient quantity of the works dedicated to development of the plasma antennas designed for work in the terrestrial atmosphere conditions. Methodical researches in that area have not done yet. This work object is to fill in a varying degree that vacuum.
