The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 01, 1987
Filed:
Jul. 24, 1983
Frank S Gutleber, Monmouth, NJ (US);
The United States of America as represented by the Secretary of the Army, Washington, DC (US);
Abstract
An interference cancelling transmitter is configured which provides electagnetic 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.degree.) 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.