Compact ULF digital communication device for underground and undersea applications
AssigneeEnig Associates, Inc.
InventorsYil-Bong Kim, Eric N. Enig
Life of this patent
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Abstract
An ultra-low or very low frequency communication device composed of: a circuit unit operative to produce an alternating current; and a dipole antenna connected to receive the alternating current and to convert the alternating current into electromagnetic radiation. The antenna is composed of an unshielded radiating conductor and a shielded return conductor connected in series with the radiating conductor, and the return conductor is shielded by a Faraday shield such as a collisionless plasma column that surrounds the return conductor to prevent any electromagnetic radiation from the return conductor.
Claims3
An ultra-low frequency (ULF) or very low frequency (VLF) communication device comprising:
- rotary switch having a plurality of conductors arranged in pairs and first and second pairs of contact elements;
- a direct current supply having a positive terminal connected to at least one contact element of the first pair of contact elements and a negative terminal connected to at least one contact element of the second pair of contact elements;
- a motor connected to said rotary switch for rotating said rotary switch;
- and
- a control circuit connected to said motor for varying an operating speed of said motor to modulate an emitting ULF or VLF wave frequency to transmit digital data,
- wherein:
- said rotary switch is configured such that during rotation of said rotary switch, each contact element is connected in turn to successive conductors such that current flows in a first direction though a conductor pair, and then flows in a second direction, opposite to the first direction, through the conductor pair, generating ULF or VLF alternating current wave.
Dependencies are inferred from the claim text.