Patent ID: 7711322

Claim:
An underwater communications system comprising: a transmitter which transmits electromagnetic and/or magnetic signals to a remote receiver said transmitter comprising a data input; a digital data compressor for compressing data that is to be transmitted and configured to reduce occupied transmission bandwidth; a modulator for modulating the compressed data onto a carrier signal; and an electrically insulated, magnetic coupled antenna for transmitting the compressed, modulated signals wherein at least one of said transmitter and said remote receiver is underwater said transmitter and said receiver being operable to communicate within a near field of said electromagnetic and/or magnetic signals, the near field of the electromagnetic and/or magnetic signals corresponding to a region around the transmitter, at least one of inverse distance squared (1/r 2 ) and inverse distance cubed (1/r 3 ) field components of the electromagnetic and/or magnetic signals is greater than an inverse distance (1/r) field component thereof.