Abstract: A wireless communication system includes a portable, typically hand-held transmitter which includes RF absorbing material and/or one or more dissipative parasitic antennas for reducing RF fields in close proximity to the operator to such an extent as to substantially preempt the effect of the operator presence, specifically the operator's hand, in field operation. As a result, the RF absorbing material and/or one or more dissipative parasitic antennas reduces the proportionate effect upon the RF radiation level caused by the operator's hand or other body part. The RF absorbing material may comprise a layer of such material upon a surface of a ground plane within a housing of the transmitter, and/or on an interior surface of the housing, and/or on an exterior surface of the housing. The dissipative parasitic antenna may comprise a printed antenna and resistive load integrated on the transmitter's printed circuit board or elsewhere in or on the housing.
Abstract: An antenna array is disclosed wherein radiators are parasitically coupled to each other, forming an efficient feed network. Parasitic coupling of patches is arranged so that some patches are fed by a plurality of other patches which are parasitically coupled thereto. The resulting array is low profile and high gain. By positioning patches on different layers with different dimensions, a broadband design for the antenna array is achieved.
Type:
Grant
Filed:
December 22, 1998
Date of Patent:
October 17, 2000
Assignees:
Her Majesty the Queen in right of Canada, as represented by the Minister of Industry through Communications Research Centre, Resonance Microwave Systems Inc.
Inventors:
Philippe LaFleur, David Roscoe, James S. Wight