摘要:
The invention concerns a method and apparatus for cascaded processing of signals in a phased array antenna system in which a plurality of antenna elements are configured as a plurality of sub-arrays. A weighting factor is applied to each of the antenna elements to form a plurality of sub-array beams, each pointed in a selected direction. For each sub-array, an output from each the antenna elements in the sub-array can be combined to produce a sub-array output signal. The sub-array output signals are selectively weighted and combined in a fully adaptive process. Subsequently, the system can estimate an angle-of-arrival direction for a signal-of-interest (“SOI”) and at least one signal-not-of-interest (“SNOI”). Based on this estimating step, the system calculates a new set of weighting factors for controlling one or more of the sub-array beams to improve the signal-to-noise plus interference ratio obtained for the SOI in the array output signal.
摘要:
A multiple beam antenna having either a main reflector or a lens is illuminated by a feed system comprising a number of primary radiators such as dipole elements. Primary radiation from each dipole element reflects from the principal reflector to produce a different respective one of the multiple secondary beams in the remote field. A disk-shaped electrically conductive director is located in the primary radiation path near each primary radiator. Each director operates both to shape the primary pattern of its respective primary radiator directly, and also to excite parasitic radiation in neighboring primary radiators so as to produce a primary radiation pattern whose shape approximates a sector of a circle, thereby producing high illumination efficiency at the main reflector. The desired sector shape of primary pattern is achieved despite relatively close lateral spacing between adjacent primary radiators of the feed system. The close spacing enables achievement of high beam crossover level between adjacent secondary beams in the remote field.
摘要:
The present application provides a semiconductor Fabry-Perot dual mode lasing device having terahertz characteristics resulting in significant advantages over the prior art including for example operation at room temperatures and the absence of re-growth processing requirements.
摘要:
Method for coherently combining signals received from two widely separated antenna apertures (204, 206). The method includes positioning a first antenna aperture (204) at a first location spaced apart a distance with respect to a second location of a second antenna aperture (206). A distance between the first antenna aperture and the second antenna aperture is selected to be at least a plurality of wavelengths at a predetermined operating frequency of the first antenna aperture and the second antenna aperture. An antenna beam or pattern (208, 210) from each antenna aperture (204, 206) is directed toward a target (212) positioned at a location remote from the first antenna aperture and the second antenna aperture. Adaptive digital processing (416) is then used to coherently combine the signals independently received by each aperture from the common source.
摘要:
A phased array antenna (10) includes a plurality of subarray lattices (16) arranged in an aperiodic array lattice (14). Each subarray lattice (16) includes a plurality of antenna elements (20) arranged in an aperiodic configuration such as formed on a multilayer circuit board (24). Electronic circuitry (26) are supported by the circuit board and mounted between the antenna elements (20) and operatively connected thereto for amplifying, phase shifting and beam forming any transmitted or received signals.
摘要:
A polarization insensitive lens is disclosed for receiving and reradiating electromagnetic energy, which may be either left-hand circular polarized or right-hand circular polarized or of any linear polarization or, in fact, of any polarization state. Each lens is comprised of a pair of spaced apart multiarm/antenna elements of opposite geometric polarization. The elements are located on opposite sides of a ground plane and spaced therefrom by 1/4 wave length. The arms of each antenna element are constructed such that both right-hand circular polarized and left circular polarized signals received by one element experience the same phase delay while being transmitted and then reradiated from the other antenna element.
摘要:
A tunable laser device (1) comprises integrally formed first and second ridge waveguides (5, 6). A longitudinally extending ridge (12) defines first and second light guiding regions (19, 20) of the first and second waveguides (5, 6) which communicate with each other. A plurality of first slots (27) extending laterally in the ridge (12) adjacent the first waveguide (5), and a plurality of second slots (28) extending laterally in the ridge (12) adjacent the second waveguide (6) produce first and second mirror loss spectra of the respective first and second waveguides (5, 6) with minimum peak values at respective first and second wavelength values. The first slots are equi-spaced apart to produce the first mirror loss spectrum, and the second slots (28) are also equi-spaced apart, but the spacing between the second slots (28) is different to the spacing between the first slots (27) so that the minimum peak values of the second mirror loss spectrum occur at different wavelength values to the wavelength values at which the minimum peak values of the first mirror loss spectrum occur, with the exception of one minimum peak value of each of the first and second mirror loss spectra, which coincide at a common wavelength value. The tunable laser device (1) produces light of that common wavelength value. In order to vary the wavelength value at which the minimum peak value of each of the first and second mirror loss spectra occur, currents with which the first and second waveguides (5, 6) are pumped are independently varied for varying the wavelengths at which the minimum peak values of the respective first and second mirror loss spectra occur, thereby providing Vernier tuning of the tunable laser device for producing light of selectable wavelengths.
摘要:
A phased array antenna may include a plurality of antenna elements, at least one respective phase shifter connected to each antenna element, and at least one respective gain element connected to each antenna element. The phased array antenna may further include at least one controller for determining and controlling both phases and gains of the phase shifters and gain elements, respectively, to provide beamsteering in a first direction for a signal of interest. The controller may also iteratively determine and control phases of the phase shifters to provide a null in a second direction for a signal not of interest, and without determining or controlling gains of the gain elements.
摘要:
A direct fed spiral antenna element array is disclosed for radiating electromagnetic energy. Each antenna element is a multi-arm spiral element having inner and outer ends. Phase shifting is obtained with internal phase control wherein switching means serve to interconnect selected ones of the inner arm ends. Each such antenna element is directly fed by a feed network which feeds currents directly to the outer ends of the spiral arms.