Material aspects of high power microwave windows*

Vladimir V. Parshin and Anatoly L. Vikharev

Institute of Applied Physics of Russian Academy of Sciences,

46 Ulyanov St., Nizhny Novgorod, 603950, Russia.

Roland Heidinger, Andreas Meier, Theo Scherer

Forschungszentrum Karlsruhe, Institute for Materials Research I, P.O. Box 3640, D-76021 Karlsruhe, Germany.

Boris M. Garin

Institute of Radio Engineering and Electronics of Russian Academy of Sciences

Vvedensky Sq.1, Fryazino, Moscow Region 141190, Russia

Jyotsna M. Dutta

Department of Physics North Carolina Central University

NC  27707, Durham, USA.

The candidate materials for high power mm-wave window materials like Sapphire, Boron Nitride, high-resistivity Silicon, CVD-Diamond and Silicon Carbide will be presented and the production technology briefly described.

The material parameters will be discussed which are most relevant for high power operation.

Experimental data of absorption values in selected grades of window materials will be reported resulting from measurements at frequencies from 40 GHz up to 380 GHz and in the temperature interval of 40-900 K.

The main absorption mechanisms for ultra-low loss materials will be described and prospects will be given for advancing these materials in the THz region.

It will be shown that CVD Diamond is the only material currently available with a transmission capability of several Megawatt in CW operation and that CVD Diamond is the primary candidate material for high-power THz applications.

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* Work supported in part by the Russian Foundation for
Basic Research under grant 05-08-65438a.