Broadband isotropic antenna with fiber-optic link to a conventional receiver
First Claim
1. A field intensity measuring system particularly adapted for near-zone electromagnetic fields comprising in combination:
- a plurality of mutually orthogonal electrically short dipole antennas responsive to a respective orthogonal RF field component of a field of unknown polarization, each dipole antenna including respective first electrical circuit means interiorally thereof;
said first circuit means including RF amplifier circuit means coupled to its respective dipole antenna for amplifying the RF field component sensed thereby, and optical energy generating means coupled to said RF amplifier circuit means, said generating means providing an optical carrier output signal which is modulated by the amplified RF signal provided by said RF amplifier circuit means;
respective optical carrier guide means coupled to said optical energy generating means;
respective photo-detector means coupled to said optical carrier guide means and being operable to demodulate the RF modulated optical carrier signal translated thereby to provide respective field component RF signals;
second circuit means coupled to said field component RF signals and being operative to provide a respective measured value signals thereof; and
third circuit means coupled to said second circuit means and being operative to process said measured values signals of said field component RF signals to provide a composite measured value signal indicative of the effective field intensity in the proximate region of said dipole antennas.
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Accused Products
Abstract
A broadband active isotropic receiving antenna for use with a conventionallectromagnetic interference receiver to measure weak near-zone electric fields of unknown polarization. The antenna consists of three mutually orthogonal active dipoles, including RF amplifier circuitry and light emitting diode means, located therein coupled to fiber optic waveguide means. The frequency range of each of the three field components is amplified and used to modulate respective light emitting diodes whose modulated infrared or visible signals are guided through the fiber optic waveguide means to photo-detectors at the far end of the fiber optic guides. These photo-detectors recover the RF modulation from the IR carrier which is then time multiplexed for input to the electromagnetic interference receiver. The DC output from the receiver is processed to provide an output voltage proportional to the square root of the sum of the squares, i.e. the Hermitian magnitude of the three mutually orthogonal electric field components.
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Citations
16 Claims
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1. A field intensity measuring system particularly adapted for near-zone electromagnetic fields comprising in combination:
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a plurality of mutually orthogonal electrically short dipole antennas responsive to a respective orthogonal RF field component of a field of unknown polarization, each dipole antenna including respective first electrical circuit means interiorally thereof; said first circuit means including RF amplifier circuit means coupled to its respective dipole antenna for amplifying the RF field component sensed thereby, and optical energy generating means coupled to said RF amplifier circuit means, said generating means providing an optical carrier output signal which is modulated by the amplified RF signal provided by said RF amplifier circuit means; respective optical carrier guide means coupled to said optical energy generating means; respective photo-detector means coupled to said optical carrier guide means and being operable to demodulate the RF modulated optical carrier signal translated thereby to provide respective field component RF signals; second circuit means coupled to said field component RF signals and being operative to provide a respective measured value signals thereof; and third circuit means coupled to said second circuit means and being operative to process said measured values signals of said field component RF signals to provide a composite measured value signal indicative of the effective field intensity in the proximate region of said dipole antennas. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification