THEORETICAL COMPARISON OF COUPLING OF A RECESSED CAVITY ANTENNA AND A CONVENTIONAL LOOP ANTENNA FOR FAST WAVES AND ION BERNSTEIN WAVES

A numerical code has been developed to calculate the loading of a cavity loop antenna in three-dimensional geometry. The loading of the cavity is calculated for fast wave and ion Bernstein wave coupling and compared with the loading of a conventional loop antenna. For fast waves, the cavity loading increases with increasing edge density, while the conventional loop loading is less sensitive to the edge density but shows a slight decrease of loading because of a steeper density gradient. For ion Bernstein waves, the two types of antenna behave similarly; however, in contrast to the loading for fast waves, the loading for ion Bernstein waves increases with decreased edge density and a steeper density gradient.