Hughes Aircraft Company

Other

Nam S Wong

Raymond K Tang

Kuan M Lee

Ruey S Chu

Jar Jar Lee

Stan W Livingston

James S Ajioka

Donald J Gibson

Sien-chang Charles Liu

James U Clark

Ray Tang

Ernie T Ozaki

A wideband, wide angle sidelobe cancellation array system is disclosed. The system includes a main array formed of a plurality of regularly spaced elements, and an auxiliary array formed of two auxiliary antenna elements spaced from the outermost elements of the main array a distance equal to one-half the spacing of the main array elements. The received signals from the main array elements are combined to form a main array signal. The contributions from the auxiliary array elements are combined to form an auxiliary array signal. The two array signals have a good amplitude and phase match over a wide frequency and angle range. The main array and auxiliary array signals are then combined to form a system array signal wherein the sidelobe energy in the main array signal has been substantially cancelled. The system can be made an adaptive one by the addition of adaptive RF phase and amplitude weighting to the auxiliary array signal prior to combining with the main array signal.

Wideband and wide angle sidelobe cancellation technique

A multiple layer dipole array that provides for a multi-frequency band phased array antenna. Several layers of dipole pair arrays, each tuned to a different frequency band, are stacked relative to each other along the transmission/reception direction. The highest frequency array is in front of the next lowest frequency array and so forth. Due to the frequency selective property of the arrays, incident high frequency signals are completely absorbed by the highest frequency array. In regard to incident low frequency signals, the insertion loss due to higher frequency arrays is small resulting in good performance of the lower frequency arrays. The multi-frequency band phased array antenna may use active or driven dipole pairs, or parasitic elements that form the multiple layer dipoles. The multiple layer dipole array of the present invention may employ corporate feed circuit boards and a corporate feed power divider, using strip transmission line circuits, for example. The multiple layer dipole phased array of the present invention may also employ a feed-through lens arrangement to simplify the feed network.

Multi-frequency band phased-array antenna using multiple layered dipole

A balun structure including a dielectric substrate having top and bottom surfaces on which are formed a splitter/combiner, a reference transmission line of length A and substantially constant characteristic impedance, and an inverting transmission line of length A and substantially constant characteristic impedance. The inverting transmission line in particular includes a first tapered planar section disposed on the top surface of the substrate and transitioning along its length from a narrow width to a wide width, and a second tapered planar section disposed on the bottom surface of the substrate and transitioning along its length from a wide width to a narrow width, such that the first and second tapered planar sections are rotated mirror images of each other.

Multi-octave bandwidth balun

An antenna for radiating electromagnetic power with plural octave bandwith is formed of an array of microstrip radiating elements each of which includes a microstrip conductor element spaced apart from a ground-plane element. A common ground-plane element is employed by all of the radiators in a row of the antenna, there being a plurality of the rows disposed parallel to each other. In each radiator, the microstrip conductor element is formed of an input section which is coupled to a feed, and an output section extending to an output end of the radiator for forming a radiating aperture of the radiator. In each output section, there is a two-dimensional enlargement of a cross-section of the radiator, one dimension of enlargement being parallel to the ground-plane element, and the other direction of enlargement being perpendicular to the ground-plane element. Enlargement in the direction parallel to the ground-plane element is accomplished by increasing the width of the conductor element. Enlargement in the direction perpendicular to the ground-plane element is accomplished by bending a portion of the conductor element away from the ground-plane element to provide for an inclination of the conductor element relative to the ground-plane element. Enlargement of the width may occur prior to or concurrently with enlargement of the dimension perpendicular to the ground-plane element.

Tapered-element array antenna with plural octave bandwidth

A dual band, phased array antenna especially adaptable for tactical radar capable of performing search, track and identification in a hostile jamming environment. The dual band array antenna is essentially two antennas sharing a common antenna aperture. The two antennas possess separate feed system and beam steering control. Thus, the beams for each frequency band can be steered independently and simultaneously. This design utilizes an ultra-wide band radiating element which can operate over approximately an octave bandwidth encompassing two adjacent microwave bands. In particular, the dual band signals can be received efficiently by the radiating element. A dual band coaxial-to-waveguide transition can be used to carry the signals to a diplexer. The dual band signals are separated at the diplexer and can be processed in separate feed networks. The advantages of this dual band phased array technique include not only good impedance characteristics but also the absence of grating lobe formation and cross coupling problems.

Dual band phased antenna array using wideband element with diplexer

A dual band array antenna is disclosed having interleaved waveguide and dipole arrays, each operating in a different frequency band. The orientation of the waveguides and dipoles is such that polarization of the signals of the two frequency bands is perpendicular to each other, thus reducing mutual coupling. The waveguides are used for the higher frequency band and their cutoff frequency is selected to be above the lower frequency band at which the dipoles operate, in order to reduce mutual coupling into the waveguides. In one embodiment the dipoles are printed on a substrate having a dielectric constant selected so that dipole spacing is the same as the waveguide spacing. This eliminates grating lobe formation in the radiation pattern of the waveguide array. A low pass filter is included in the dipole feed circuit to reject the frequencies at which the waveguides operate. As a result of the invention, two beams of two different frequency bands are independently and simultaneously steerable in a single antenna aperture.

Interleaved waveguide and dipole dual band array antenna

A phased array antenna which is adapted to provide electronic scanning over a limited scan range with a minimum number of control devices and yet maintain fairly low sidelobes is disclosed wherein the respective radiating elements are grouped into steerable subarrays. Phase steering of the subarrays is performed in discrete steps by means of phase shifters with one or two bits interspersed within the feed network. The phase state of these subarray phase shifters is selected to improve the antenna gain and suppress the grating lobes. Overlapping of the radiating elements of the subarrays is also employed to further suppress grating lobes throughout the limited scan range.

Growing community of inventors

Fullerton, CA, United States of America

Nam S Wong