Accession Number : ADD010406

Title :   Interference Cancelling Transmitter.

Descriptive Note : Patent Application,


Personal Author(s) : Gutleber,Frank S

Report Date : 25 Jul 1983

Pagination or Media Count : 12

Abstract : An interference cancelling transmitter is configured which provides electromagnetic compatibility (EMC) among different communications apparatus in the same area as well as providing a low probability of intercept (LPI) in a dense communications environment where secure communications is required between users. This is accomplished by means of a communications transmitter coupled to a transmitting antenna configuration comprised of an omnidirectional antenna and a notch antenna having a single deep null over a small angular beamwidth. RF power is fed equally thereto so that the radiated power from each antenna is the same but the phase is mutually inverted (180 deg) so that a cancellation of the radiated power occurs in all directions of space except over the angular region where the null of the notch antenna is located. The null can be varied in direction and results in a relatively narrow pencil-like radiation pattern being radiated to a predetermined receiver. (Author)

Descriptors :   *Patent applications, *Directional antennas, *Radio interferometers, *Radio transmitters, *Phased arrays, Cancellation, Communication equipment, Radiofrequency, Antenna configurations, Orthogonality, Secure communications, Electromagnetic compatibility, Interception probabilities, Interference, Radiation, Electromagnetic interference, Beams(Radiation), Vulnerability, Radiofrequency power, Low rate, Interference, Transmitters, Regions, Angles

Subject Categories : Radiofrequency Wave Propagation
      Radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE