Trw Limited

Carlton H Walter

Donn V Campbell

Robert V Devore

In the preferred embodiment of the invention, a broadband dipole antenna 10 for transmitting and receiving electromagnetic energy constructed of coaxially aligned radiating elements 14 and 16 is provided. Each of the radiating elements 14 and 16 has a charge collector 40 and 42 affixed to its free end, that function to collect charges forming a current sink for collecting the current generated by the radiating elements. Coupled with the radiating elements is an isolation choke 44 to isolate the radiating elements against electrical disturbances caused by the antenna support platform 130 and 138 effecting a match of the impedance between the radiating elements and the transmission lives. Another preferred embodiment is a monopole 86 equipped with a charge collector 96. The dipole 10 and monopole 86 are provided pairs of open-sleeves 28 and 26 and 92 and 94 to enhance the instantaneous bandwidth of the radiating elements.

Charge collector equipped, open-sleeve antennas

A spiral antenna is provided which is capable of providing dual circular polarization operation with a large number of operating modes. The spiral antenna includes at least eight conductive spiral antenna arms extending outward about an axis of rotation. Each antenna arm has an inner end and an outer extending end and a plurality of arm width modulations formed therebetween for achieving dual circular polarization operation capability. Electrical feeds are coupled to the inner end of each of the spiral antenna arms. A feed network may be further connected to the electrical feeds for providing predetermined phase excitations to the corresponding spiral antenna arms so as to achieve the desired operating modes.

Multi-mode dual circularly polarized spiral antenna

A compact high frequency multi-turn loop antenna is provided for use on a conductive structure such as the airframe of an airborne vehicle. The antenna employs a plurality of interconnected conductive loops which are magnetically coupled to a conductive structure. One end of the conductive loops is coupled via tuning and impedance matching circuits to a transceiver for transmitting and receiving signals therefrom. The other end of the conductive loops is coupled to ground. When transmitting a signal, the transceiver excites a current on the conductor which induces a magnetic field that excites the conductive structure. Upon receiving a signal, the conductive structure is excited which in turn generates a magnetic field through the plurality of loops and induces a current on the conductor. The antenna may advantageously be mounted within a conductive cavity structure which in turn is connected to the conductive structure.

High frequency multi-turn loop antenna in cavity

A generally planar antenna structure having at least six radial antenna elements, each of which uses log-periodic principles to provide a broad bandwidth of operation. Each antenna element has a radial arm and integral, arcuate teeth extending in opposite directions from the radial arm, such that the spacing, width and length of the teeth increases with increasing radial distance from the center of the structure. The teeth are preferably interleaved with teeth in adjacent antenna elements. A feed region of the structure is provided near its center, to connect the antenna elements through a connection matrix to input/output terminals and provide operation in multiple modes and multiple polarization senses. The antenna structure is capable of operating in high order modes, to provide multifunctional operation and enhanced performance in angle-of-arrival systems, and is capable of transmitting and receiving both right-hand and left-hand circularly polarized signals, and all dual linearly polarized signals, all over a broad frequency band.

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Poway, CA, United States of America

Carlton H Walter