Northrop Grumman Systems Corporation

Westinghouse Electric Corporation

Other

Patrick J Knowles

Timothy G Waterman

Arnold L Ferreri

Lynette M Jones

Charles L Dietz

David P Lopez

An antenna system can include a first panel of radiators that extend from a vertex in a first substantially linear direction. The antenna system can also include a second panel of radiators extending from the vertex in a second substantially linear direction. The first panel of radiators and the second panel of radiators form an angle between about 1 degree and about 45 degrees to enhance gain.

Antenna system

A hybrid filter element includes an impedance transformer and a phase cancellation loop having a first portion and a second portion is disclosed. The first and second portions are designed to provide a phase difference between the two portions of about 180&deg; at a mid-band frequency. The first portion forms part of the impedance transformer and is typically smaller than the second portion. The first and second portions can be designed to have either an equal power split or an unequal power split between the portions.

Hybrid multi-pole gain zero filter element

Parasitically driven dipole array

A method and apparatus for accomplishing a 90.degree. relative phase shift employing a high characteristic impedance outer leg of length .lambda./2 and a low characteristic impedance through leg of length .lambda./4. The high characteristic impedance outer leg is directly connected to the input and the output. The low characteristic impedance through leg is connected to the input and output with first and second diode paths. When the first and second diode paths are in the on state, the low characteristic impedance through leg receives a majority of the input power. Because of the impedance disparity between the high characteristic impedance outer leg and low characteristic impedance through leg, only a small amount of power is routed through the high characteristic impedance outer leg when the first and second diode paths are in the on state and the combined signal phase is not substantially effected. When the first and second diode paths are in the off state, the input signal is routed through the high characteristic impedance outer leg. Because the relative lengths of the high characteristic impedance outer leg and the low characteristic impedance through leg differ by .lambda./4, a relative phase shift of 90.degree. is provided at the output.

90.degree. phase shifter apparatus and method using a directly coupled

A tilted helical element antenna array has increased effective aperture. By tilting individual helical radiators relative to one another, the region of aperture overlap may be decreased to thereby increase the effective aperture of the array. Helical radiators are disposed at a radiator spacing which is less than the operating wavelength .lambda.. At such a small spacing, the apertures of each of the helical radiators overlap. To decrease this aperture overlap region and thereby increase the effective aperture of the array, each of the helical radiators are tilted relative to one another. Thus, a compact antenna having an increased effective aperture is provided.

Tilted element antenna having increased effective aperture and method

An efficiently radiating helical antenna includes a conductive helix receiving signals to be radiated at a first end of the conductive helix device for capacitively pulling fields generated by the signals towards a second end of the conductive helix opposite the first end. The device may be a conductive tube inserted into the second end of the conductive helix or a disjointed conductive helix surrounding the conductive helix. This scheme works especially well for a conductive helix having a circumference on the order of one wavelength.

Helical antenna having a parasitic element and method of using same

A microwave buffer for use between transmitter modules and an impedance combiner. The buffer is comprised of a plurality of input segments, a plurality of output segments and an elongated transmission segment connecting the input segments to the output segments. The geometry of the buffer along with bridges located proximate to the transmitter modules eliminate the destructive effects of reflected waves set up by an unbalanced impedance combiner when one of the transmission modules becomes inoperative. The hourglass shape of the buffer causes the phases of the signals from each transmission module to be equal from any transmission port to any output. The bridges force the sum of the mutual couplings to be low in amplitude on any transmission module.

Microwave buffer

An antenna comprising a ground plane having a base portion and a cylindrical obstruction that extends from the base. The obstruction is oriented such that its longitudinal axis is perpendicular to the base ground plane. The antenna also has a conducting transmission along the length of the exterior of the obstruction. A feedpoint located near the base ground plane transmits a voltage signal between the transmission element and the exterior of the obstruction. A short circuit is provided between the transmission element and the obstruction at a point distal to the feedpoint.

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Severn, MD, United States of America

Patrick J Knowles