US Patent 7170363 Guides for r.f. magnetic flux

Microstructure materials which can be tuned to a particular range of r.f. frequencies to display particular magnetic permeabilities have been proposed. A typical material is made of an array of capacitive elements e.g. spirals or rolls of conducting material on a non-conducting substrate. These materials can be used as a guide which is effective for the particular band of frequencies to which it is tuned. In one example, the rolls (2a to 2c) guide magnetic flux along ducts (1, 2, 3) while rolls (4a, 5a) guide magnetic flux along ducts (4, 5). Flux can thus be guided upwardly along duct (2), along ducts (4 and 5), and down ducts (1, 3), or vice versa.