Abstract: An antenna system, with a loop antenna and a loop current, is provided for transmitting an electromagnetic signal through a medium. The loop antenna has an E field transducer that generates an E field, and an H field transducer that generates an H field. The E and H fields are orthogonal in space and have at least one of a magnitude and phase relationship that is matched to an intrinsic impedance of a medium to generate a propagating wave. In an insulating medium the loop current lags an E field plate voltage by 90° to produce in phase E and H fields. In a conductive medium current is applied to the loop with a 135° phase lag with respect to a voltage across the E field plates. The H field is generated by the current component and leads current by 90°.

Abstract: An extended underwater electromagnetic transducer is provided with an electrically insulated transmission line typically connected to a transmitter or receiver or transceiver system. The transmission line allows near-field communications with another transmitter or receiver or transceiver system. The transmission line provided is relatively long, the through water signal path length can be significantly reduced.

Abstract: An underwater communication method is provided. EM signals are transmitted via a seabed using an underwater electrically insulated magnetically coupled antenna. By making use of the low loss properties of the seabed, EM signal attenuation can be reduced and consequently the transmission range can be increased. The underwater electrically insulated magnetically coupled antenna may be located within a body of water or may be buried in the seabed.

Abstract: An underwater communications system is provided that transmits electromagnetic and/or magnetic signals to a remote receiver. The transmitter includes a data input. A digital data compressor compresses data to be transmitted. A modulator modulates compressed data onto a carrier signal. An electrically insulated, magnetic coupled antenna transmits the compressed, modulated signals. The receiver that has an electrically insulated, magnetic coupled antenna for receiving a compressed, modulated signal. A demodulator is provided for demodulating the signal to reveal compressed data. A de-compressor de-compresses the data. An appropriate human interface is provided to present transmitted data into text/audio/visible form. Similarly, the transmit system comprises appropriate audio/visual/text entry mechanisms.

Abstract: A wearable article of clothing and the like is configured to be worn by a person underwater or underground; An antenna with at least one loop, is coupled to the wearable item. The antenna provides transmission or receipt of electromagnetic signals and has a size and geometry that maximizes antenna transmission area while minimizing a restriction on movement by the person wearing the wearable article. The antenna carries an alternating current that provides conductive attenuation and has three different field components. Each field component has a different geometric loss when moving a distance r from the antenna. R is a propagating distance from the antenna.

Abstract: An underwater connector (10) comprising a magnetic coupler for passing communications signals and/or power from one part (12) to another part (13) using magnetic coupling and without requiring direct electrically conductive contact between the parts (12, 13).