Physically Adaptive Antennas.
Final rept. Jun-Oct 93,
MARYLAND UNIV COLLEGE PARK DEPT OF ELECTRICAL ENGINEERING
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A reconfigurable antenna concept, consisting of a semiconductor illuminated by an optical or electron source, was studied. With appropriate-illumination, mobile charge carriers excited from the valence band to the conduction band can form a conducting antenna pattern in the semiconductor material. Calculations of gain and radiation resistance for linear dipole and bow-tie layouts were completed to estimate source power requirements and practical wavelength limits for such an antenna. Significant findings were that source power for writing a reconfigurable antenna increases as the square of the radiation wavelength and that semiconductor material permittivity limits antenna efficiency to about one-tenth that of a comparable free-standing antenna. Frequency agility in the antenna may be possible using an electronically controllable liquid crystal display, semiconductor laser array, or electron emitter tips.
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