THEORETICAL AND EXPERIMENTAL-STUDY OF SILICON-BASED ANGULAR FILTERS

We study periodic structures constructed by low resistivity Si wafers which allow only the transmission of electromagnetic waves incident at a certain angle. We call those materials angular filters. The angular width of the transmission peak can be controlled by changing the thic kness of the structure and/or by changing the resistivity of Si wafers . The basic idea behind the unusual properties of those materials lies on the Borrman effect or anomalous transmission of x rays through the crystals. Measured responses are in good agreement with theoretical s imulations. Although the present structure was designed and built to w ork at around 100 GHz, similar structures can be designed for any othe r frequency region. (C) 1996 American Institute of Physics.