892 results about "Beamwidth" patented technology

A dual-band antenna is provided that combines two normally disparate communications modes into a single compact aperture minimizing overall mass and volume, while maintaining high performance efficiency and reciprocity of each individual mode. The antenna is compatible with both optical (near-IR / visible) and RF (microwave / millimeter-wave) transceiver subsystems for high bandwidth communications, applicable primarily to long- to extremely long-range (space-to-ground) link distances. The optical link provides high bandwidth while the RF provides a lower data-rate weather backup, accommodation for traditional navigation techniques, and assistance in cueing the extremely tight optical beam by matching the RF beamwidth to an optical fine-steering mechanism field-of-regard. The configuration is built around a near-diffraction-limited high performance primary mirror shared by both a direct-fed RF antenna design and a Cassegrain optical telescope. Material properties are exploited to combine the optical secondary mirror with the RF feed structure, providing a collimated optical beam interface at the antenna vertex.

An antenna system for wireless networks having a dual stagger antenna array architecture is disclosed. The antenna array contains a number of driven radiator elements that are spatially arranged in two vertically aligned groups each having pivoting actuators so as to provide a controlled variation of the antenna array's azimuth radiation pattern.

A reflector arrangement is configured for attachment to a wireless communications terminal having a patch antenna. The patch antenna includes a patch radiator in a substantially parallel relationship with a ground plane, and the patch antenna produces a radiation beam of a predetermined beamwidth. The reflector arrangement is configured, when attached to the terminal, to produce a radiation beam of reduced beamwidth relative to the predetermined beamwidth. The reflector arrangement comprises a main reflector and a sub-reflector for reflecting radiation towards the main reflector, and the reflector arrangement is configured such that, when attached to the terminal, the patch antenna acts as a feed antenna for the sub-reflector. The sub-reflector is arranged to collect the radiation from the patch antenna and to reflect the beam towards the main reflector such that the main reflector produces the radiated beam of reduced beamwidth.

The present invention is directed to a radar system that includes an antenna array having a plurality of antenna elements and a plurality of transmit antenna phase centers. A transmitter portion is coupled to the antenna array. The transmitter portion is configured to transmit a plurality of transmit beams characterized by a transmit beam pattern. The transmit beam pattern has a predetermined transmit beamwidth that is a function of the number of orthogonal transmit waveforms. The predetermined transmit beamwidth substantially fills a predetermined angular volume. Each of the plurality of transmit beams includes a corresponding one of the plurality of orthogonal transmit waveforms. Each of the plurality of transmit beams is transmitted by a corresponding one of the plurality of transmit antenna phase centers. The number of orthogonal transmit waveforms is less than the plurality of antenna elements. A receiver portion is also coupled to the antenna array. The receiver portion is configured to extract a plurality of orthogonal receive signal components from a received signal provided by the antenna array. The plurality of orthogonal receive signal components corresponds to the plurality of orthogonal transmit waveforms. A plurality of extracted orthogonal receive signal components are digitally beam formed to implement a virtual antenna array and generate a receive signal having a receive beamwidth. The virtual antenna array includes a plurality of virtual antenna elements greater than the plurality of antenna elements. The receive beamwidth is a function of the plurality of virtual antenna elements.

A dual-band feed horn having a connection surface configured for connection to a waveguide and a first surface coupled to the connection surface. The first surface has a cylindrical surface with a length and a first diameter chosen to propagate TE11 modes for both a low frequency band and a high frequency band. The horn has a bandwidth ratio of the high-frequency band to the low frequency band in the range of 1.6-4.0. The horn also has a substantially conical surface coupled to the first surface at a first slope discontinuity. The conical surface includes multiple surfaces each having a respective slope and coupled to adjacent surfaces by a respective plurality of slope discontinuities each having a respective diameter. The slopes and diameters are chosen to generate primarily TM1,m modes (m=1, 2, 3, etc.) in the high-frequency band and primarily higher order TE1,n modes (n=2, 3, etc.) in the low-frequency band such that the low frequency band and the high frequency band have approximately equal beam widths.

An antenna assembly includes at least two active or main radiating omni-directional antenna elements arranged with at least one beam control or passive antenna element used as a reflector. The beam control antenna element(s) may have multiple reactance elements that can electrically terminate it to adjust the input or output beam pattern(s) produced by the combination of the active antenna elements and the beam control antenna element(s). More specifically, the beam control antenna element(s) may be coupled to different terminating reactances to change beam characteristics, such as the directivity and angular beamwidth. Processing may be employed to select which terminating reactance to use. Consequently, the radiator pattern of the antenna can be more easily directed towards a specific target receiver / transmitter, reduce signal-to-noise interference levels, and / or increase gain. A Multiple-Input, Multiple-Output (MIMO) processing technique may be employed to operate the antenna assembly with simultaneous beam patterns.

A high data rate communication system operating at frequencies greater than 70 MHz and at data rates of about 1.25 Gbps or greater. Preferred embodiments include modulators with a resonant LC circuit including a diode which is back-biased for “off” (i.e., no transmit) and forward biased for “on” (or transmit). The modulator is a part of high performance transceivers for wireless, millimeter wave communications links. A preferred embodiment provides a communication link of more than eight miles which operates within the 71 to 76 GHz portion of the millimeter spectrum and provides data transmission rates of 1.25 Gbps with bit error rates of less than 10−10 . A first transceiver transmits at a first bandwidth and receives at a second bandwidth both within the above spectral range. A second transceiver transmits at the second bandwidth and receives at the first bandwidth. The transceivers are equipped with antennas providing beam divergence small enough to ensure efficient spatial and directional partitioning of the data channels so that an almost unlimited number of transceivers will be able to simultaneously use the same spectrum. In a preferred embodiment the first and second spectral ranges are 71.8+ / −0.63 GHz and 73.8+ / −0.63 GHz and the half power beam width is about 0.2 degrees or less. Preferably, a backup transceiver set is provided which would take over the link in the event of very bad weather conditions. In other embodiments especially useful for mobile applications at least one of the transceivers include a GPS locator.

An antenna architecture with a dual-band patch antenna structure having a broadened low-frequency beamwidth is disclosed. The dual band antenna structure comprises a high frequency patch antenna cavity stacked inline above a low frequency patch antenna cavity. An N-shaped metallic wall surrounds the low frequency patch antenna cavity and broadens the emission radiation beamwidth of the low frequency emission. As such, these dual band antenna structures can emit radiation with a beamwidth of approximately 90 degrees in the low frequency band of 700 MHz to 900 MHz as well as the high frequency band of 1.7 GHz to 2.2 GHz.

Substantial improvements in frequency reuse in microwave communications systems is achieved by canceling co-channel interference and transmitter leakage. Interferometric beam-narrowing reduces beamwidth without reducing peak magnitude of the beam pattern. Frequency-dependent beam-shaping compensates for frequency-dependent distortions of the beam pattern thereby improving bandwidth. A spatial demultiplexing technique utilizes spatial gain distributions of received signals to separate signals, even from co-located transmit sources, and uses microwave lensing to enhance received spatial gain distributions. Predetermined cross-polarization interference is used to separate differently-polarized receive signals. A reference branch provides a cancellation signal to a receiver to cancel transmitter leakage signals. An error signal controls an impedance-compensation circuit that is responsive to changes in antenna impedance but not to receive signals. A dc bias magnetic field applied to a magnetic permeable material adjusts non-linear distortion in a cancellation circuit for canceling distortion in a transmitter leakage signal. Discreet impedance elements approximate a circuit having distributed impedance.

A frequency scanning traveling wave antenna array is presented for Y-band application. This antenna is a fast wave leaky structure based on rectangular waveguides in which slots cut on the broad wall of the waveguide serve as radiating elements. A series of aperture-coupled patch arrays are fed by these slots. This antenna offers 2° and 30° beam widths in azimuth and elevation direction, respectively, and is capable of ±25° beam scanning with frequency around the broadside direction. The waveguide can be fed through a membrane-supported cavity-backed CPW which is the output of a frequency multiplier providing 230˜245 GHz FMCW signal. This structure can be planar and compatible with micromachining application and can be fabricated using DRIE of silicon.

A method of automatic alignment of two directional beams having a known path attenuation, and an antenna gain pattern, for mutual transmission, comprises: determining a beam width between two angles of minimal detectable connection on either side of a beam maximum; then mapping points onto a scan field in a regular pattern, the pattern based on the beam width, such that a beam with the determined beam width is detected once if the beam is in the scan field at all; scanning the first antenna over the mapped scan points; and for each point allowing the second antenna to scan over all of its own set of mapped scan points, thereby providing a coarse alignment of the two antennas to achieve at least a minimal mutual connection. The coarse alignment may be followed by a fine alignment to maximize the signal.