Wafer‐scale silicon optically controlled absorber/reflector surface

A wafer‐scale silicon optically controlled wafer antenna array, which can be used to reflect or absorb incident microwave energy at 10 GHz, is presented. A 2‐μm‐thick copper printed dipole array, loaded with matched polysilicon resistive terminations, is fabricated on a 4‐inch‐high resistivity, 6kΩ‐cm, 525‐μm‐thick silicon wafer. A second unprocessed wafer, optically controlled by an optical source, provides a shutter mechanism so that the assembly acts as a reflector/absorber surface or spatial switch. The arrangement is shown to provide 25‐dB isolation between reflecting and absorbing states at 10.1 GHz. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 44: 318–320, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20622