398 results about "Transmit array" patented technology

A transmitter is provided for simultaneously transmitting a plurality of signals in a plurality of directive beams to corresponding destination stations, each destination station located in a separate fan within a service area. The transmitter includes a plurality of beamformers, each beamformer receiving one of the signals to be transmitted to an associated fan, each of the beamformers having a plurality of outputs for each different signal to be transmitted. A plurality of Butler matrices each receive one of the plurality of outputs from the plurality of beamformers for each different signal to be transmitted, each Butler matrix having a plurality of outputs in phased relationship to one another, wherein each of the signals to be transmitted is simultaneously provided across the outputs of each Butler matrix in a phased relationship. An antenna is provided with an aperture within which a two-dimensional array of antenna elements are disposed, wherein equal fractions of adjacent antenna elements are connected to the outputs of each Butler matrix, and wherein each of the plurality of signals are simultaneously transmitted by the entire two-dimensional array of antenna elements. Each of the plurality of beamformers receives steering control signals for steering the direction of each beam within its respective fan.

In a conventional automotive radar, a return occurs in a phase difference characteristic necessary for a super-resolution method, resulting in an increase of a detection error, or an extremely narrowed azimuth detection range. A transmitting array antenna, and receiving array antennas are composed of antenna elements respectively, and aligned in a horizontal direction. The weighting of receiving sensitivities of the antenna elements of the receiving array antenna 1 is A1, A2, A3, and A4, which are monotonically decreased from an inner side toward an outer side as represented by A1≧A2≧A3≧A4. On the other hand, the receiving array antenna 3 is symmetrical with the receiving array antenna with respect to the receiving array antenna 1.

A multiple resonances type ultrasonic transducer for a ranging measurement with high directionality using a parametric transmitting array in air, includes an ultrasonic actuator unit formed with a regularly mixing array of first unit actuators having a resonance frequency of f₁ and second unit actuators having a resonance frequency of f_2. The ultrasonic actuator unit generates a difference frequency wave (f_d=f₁−f₂) with high directionality by forming a parametric transmitting array in air through generating two ultrasonic waves with high pressure in air. Further, the transducer includes an ultrasonic sensor unit formed with one or more unit sensors having a resonance frequency of the difference frequency (f_d=f₁−f₂), for sensing a reflected ultrasonic pulse'signal from a target.

An inspection system uses microwave radiation to capture a microwave image of a transportable item. The system includes a transmit scanning panel including a transmit array of transmit antenna elements, each being programmable with a respective phase delay to direct a transmit beam of microwave radiation toward a target of the transportable item for transmission of the microwave radiation through the target. The system further includes a receive scanning panel including a receive array of receive antenna elements, each being programmable with a respective phase delay to receive a receive beam of microwave radiation from the target. A processor measures the amplitude and phase of the microwave radiation in the receive beam to determine a relative value of a pixel within the microwave image of the transportable item based on a reference value of the pixel.

The invention provides a method for constructing a thinned MIMO (Multiple Input Multiple Output) planar array radar antenna, which is on the basis of a phase center approximation principle and combines an MIMO antenna thought. The antenna arrangement optimal design is carried out by adopting the MIMO antenna thought. When all transmitting array elements simultaneously (or in turns) transmit orthogonal signals and receiving array elements simultaneously receive echo signals, a virtual planar array with uniform intervals is subjected to equivalence processing by utilizing the phase center approximation principle. According to the thinned MIMO planar array radar antenna constructed according to the invention, few transmitting antenna array elements and few receiving antenna array elements can be adopted and the equivalent full-array-element arrangement planar antenna array is virtually realized. Compared with the planar array antenna which is the same size as the equivalent virtual planar array and is directly arranged, the thinned MIMO planar array radar antenna constructed according to the method disclosed by the invention has the advantage of greatly reducing the requirement on the number of the array elements.

The invention discloses a self-correction method of a multi-input multi-output radar system array error, relating to the radar technical field. The method aims to carry out self correction of the reliant amplitude and phase error of a receiving array azimuth on the premise that the transmitting array of a multi-input multi-output radar system. The implementation process of the method is as follows: firstly, by means of the two corrected transmitting array elements of the multi-input multi-output radar system, orthogonal signals are transmitted; then, the echo signals of the transmitting array elements are separated by means of the orthogonality of transmitting signal through adopting a matched filtering method; an auto correlation matrix and a cross correlation matrix are established by means of the echo signals; a real guide vector and a target angle of an array are estimated by means of a rotary invariant subspace method; finally, by means of the real guide vector and the target angle of the array obtained through estimation, the array azimuth reliant amplitude and phase error can be corrected. The self-correction method can be used in the array error correction field of a multichannel radar system.

A radar system includes at least one transmit array comprising a plurality of metamaterial elements. The radar system further includes at least one near-field stimulator for inputting electromagnetic signal to the transmit array so that a sub-wavelength target is illuminated with an electromagnetic wave.

A radar transmitter transmits a radar signal through a transmitting array antenna at a predetermined transmission period, and a radar receiver receives a reflected wave signal which is the radar signal reflected by a target through a receiving array antenna. A transmitting array antenna and a receiving array antenna each include multiple subarray elements, the subarray elements in the transmitting array antenna and the receiving array antenna are linearly arranged in a first direction, each subarray element includes multiple antenna elements, the subarray element has a dimension larger than a predetermined antenna element spacing in the first direction, and an absolute value of a difference between a subarray element spacing of the transmitting array antenna and a subarray element spacing of the receiving array antenna is equal to the predetermined antenna element spacing.

In the method and system, a transmitter demultiplexes an input data stream into M substreams, where each of the M substreams have a data rate lower than a data rate of the input data stream. The substreams are transmitted as signals from a transmit array of M antennas to be received by a receiver array at a receiver in the system, based on a set of transmission parameters. The transmitter adjusts at least one of the transmission parameters based on a condition experienced by the receiver so as to increase data throughput in the system. The adjustable parameters include the number of antennas to employ, the on/off patterns for the antennas, and eigenmode values for the antennas used in order to determine transmit power. Accordingly, system data throughput may be improved while maintaining transmit power and system bandwidth constant.

The present invention provides a wideband signal synthesizing method based on multi transmitting and multi receiving frequency-division radar, which comprises the following steps: 1) synchronously transmitting M subband signals from M transmitting array elements of transmitting array at the transmitting side of multi transmitting and multi receiving radar; 2) receiving echo signal by N receiving array elements in the receiving array at the receiving end of multi transmitting and multi receiving radar, and obtaining N*M path of receiving signals corresponding to different frequency bands and different array elements as each receiving array element is set with M receiving channels; and 3) executing beam forming processing and matched filtering processing, obtaining M narrow-band signals, adding the frequency spectrum of M narrow-band signals for obtaining the synthesized wideband signal, wherein the final wideband signal is obtained through multiplexing the wideband signal with the reciprocal frequency spectrum window. The invention effectively overcomes the problem that side-lobe generates when a plurality of narrow bands synthesize a broadband signal. Therefore a plurality of narrow-band receiving and transmitting channels can be used for realizing high-resolution distance image according to the invention thereby greatly reducing the requirement of imaging radar to the capability of broadband device.

A monopulse radar system for detecting an azimuth depending upon amplitude difference or phase difference between signals respectively received by plural receiving antennas, includes: a transmitting array antenna and a receiving array antenna each including antenna elements forming an antenna train, at least one antenna switch disposed among the elements of the transmitting array antenna and/or the receiving array antenna, and a switch controller for turning ON/OFF the antenna switch to change an aperture length of the transmitting array antenna and/or the receiving array antenna thereby changing a beam shape thereof. The antenna elements of the transmitting array antenna and the receiving array antenna are formed on a dielectric substrate. A dielectric length between the antenna train formed by the antenna elements and the antenna switch is ½ dielectric wavelength.

The invention provides a multi-target positioning method of a bistatic multi-input multi-output radar, comprising the following steps of: (1) transmitting mutually orthogonal phase-coded signals by M transmitting array elements, and receiving the phase-coded signals by N receiving array elements, wherein the distances of the M transmitting array elements and the N receiving array elements are all of half wavelengths; (2) carrying out matched filtering on the received phase-coded signals by a matched filter of a receiver of each receiving array element; (3) carrying out multistage Wiener filtering on a matched signal data covariance matrix space, and carrying out forward recursion to obtain a signal subspace; (4) carrying out high-resolution DOA (Direction of Arrival) estimation by using an ESPRIT algorithm, wherein a pairing algorithm is used for carrying out the automatic pairing on two-dimensional parameters; and (5) realizing multi-target positioning according to cross points at two angles so as to obtain the positions of space targets. The multi-target positioning method provided by the invention has the advantages of low computation complexity, high computation speed, high estimation accuracy and can be used for positioning the sea-surface or low-altitude targets during tracking and guidance.

The invention discloses a mobile satellite communication phased array antenna, which relates to a high performance satellite communication antenna device of a mobile satellite communication system in the communication field. The invention comprises a receiving array, a transmitting array, a feed network, a radio frequency receiving component, a radio frequency transmitting component, a servo tracking and beam controlling system, and an antenna seat and other components. The invention adopts a form of a one-dimensional phased array scanning antenna, a track mode of mutually combining azimuth plane mechanical tracking and pitching surface phased array electric track while scan is formed by adopting a non-planar array form structure, and the receiving and the transmitting of signals are completed. The invention also has the advantages that the tracking speed is quick, the electrical performance is good, and the outline is low, etc. The invention is in particular applied to the manufacturing of the high performance satellite communication antenna in the mobile satellite communication system.

The invention provides an electromagnetic vortex imaging method under a single-antenna receiving condition. The technical scheme comprises the following steps: S1, N identical antennas are evenly distributed on a circumference to form a transmitting array; S2, electromagnetic vortexes of different frequencies and different orbital angular momentum modes are transmitted in turn using the transmitting array, and a single antenna in the center of the transmitting array receives each target echo, wherein the amplitude and phase information of the target echo received constitute frequency-orbital angular momentum mode two-dimensional echo data; S3, phase compensation is made for the received two-dimensional echo data according to the prior information of the parameters of the transmitting array and the elevation angle of a target to get preprocessed two-dimensional echo data; and S4, two-dimensional Fourier transform is carried out on the preprocessed two-dimensional echo data to get a distance-azimuth two-dimensional image of the target. The receiving process is simple. The method is easy to implement. Reference can be provided for the development of target recognition and new-system radar imaging technologies.

The invention discloses a method for united correction of MIMO radar transceiving array errors, wherein the method can improve array error correction precision. Echo signals of an antenna array are obtained, the echo signals are utilized to construct a receiving array covariance matrix and a transmitting array covariance matrix, the covariance matrixes of both a receiving array and a transmitting array are utilized to respectively correct the received and transmitted array errors, angular measurement inaccuracy caused by array errors is avoided, and the array errors of the receiving array and the transmitting array can be simultaneously corrected; orientation dependence occurs in an array guiding vector due to the array errors in collection, the antenna array rotates through J angles by enabling the antenna array comprising M array elements to be arranged on a turntable, the echo signals of the antenna array at each angle are respectively received, sample data of plenty of orientation angles of a plurality of orientations can be collected, and array error correction precision is improved. The method is suitable for being popularized and applied in the field of array signal processing.

An automotive radar having a high level of azimuth accuracy and a broad detectable range by virtue of preventing leaks of unnecessary waves to receiving antennas is to be provided. A transmitting array antenna 1 and receiving array antennas 2a, 2b are arranged on an antenna plate (grounding conductor plate) 3 which serves to ground the antennas, and radio wave absorbers 4 are arranged on two sides of the edges 15 of the antenna plate 3. The radio wave absorbers 4 may be configured of, for instance, a sponge material containing radio wave absorbing grains.

Embodiments of the present invention provide retrodirective noise-correlating radar that include: (1) a transmit antenna array that quiescently transmits random noise; (2) a receive antenna array, in a desired spatial relationship with the transmit antenna array, for collecting the reflected noise from a target; and (3) RF electronic components interconnecting antenna-element pairs between the receive and transmit arrays. In one group of embodiments, the radar automatically transforms the broad pattern from each element of the array (when transmitting or receiving random noise), to a narrow pattern characteristic of the entire array. In a second group of embodiments, a presence of a target and its range are determined quickly by a quasi-coherent build-up of signal in the time or frequency domains. In third group of embodiments a target angle and velocity vector are determined by cross correlation between two or more electronic channels connecting the transmit and receive arrays.

The invention discloses a coherent and incoherent mixed target DOA estimation method based on a coprime MIMO array. Compared with the actual sparse coprime MIMO array, the DOA estimation method constructs an evenly and densely distributed virtual MIMO array, the array contains more numbers of transmitting array elements and receiving array elements, DOA estimation is carried out using obtained equivalent multiple snapshot data of the virtual MIMO array, the problem of the coherent and incoherent mixed target DOA estimation is solved, and the limit of the actual array number of the coprime MIMOarray to the maximum number of distinguishable targets can be broken through. The virtual MIMO array with different transmitting and receiving array elements can also be obtained, according to the number of different maximum distinguishable coherent targets and the total number of maximum distinguishable coherent and incoherent targets, the demand of the DOA estimation for the coherent and incoherent targets is met through flexibly selecting the number of transmitting and receiving array elements of the virtual MIMO array, and the flexibility of the DOA estimation is improved.

A Class-E amplifier has bee adapted for use in the radio frequency section of a magnetic resonance imaging (MRI) system. A drive signal is produces by modulating the envelope of a radio frequency carrier signal and then applied to a switch in the Class-E amplifier. The switch is connected in series with a choke between a supply voltage terminal and circuit ground with an output node formed between the choke and the switch. The output node is coupled to circuit ground by a shunt capacitor. In a preferred embodiment, a pair of such amplifiers, that are Π radians out of phase, are connected to each rung of a transverse electromagnetic transmit array type radio frequency coil of the MRI system.

In magnetic resonance data acquisition, decoupling between the transmit and receive coils is achieved by using a transmit array system wherein induced currents from the transmit coils cancel each other, resulting in a total of zero current in the receive coil. Forward and reversed polarized transmit coil pairs are set to cancel the individual currents of each other, or of a receive coil. Linearly polarized fields can also be used to effect the decoupling. The decoupling allows the magnetic resonance data acquisition system to be operated for concurrent excitation of the nuclear spins and reception of the resulting magnetic resonance signals.

The invention provides a multi-target location method of a bistatic common-address multi-input-multi-output radar. The method comprises the following steps of: transmitting mutual orthogonal phase coded signals by M transmitting array elements; receiving the phase coded signals by N receiving array elements; performing matching filtering on the received phase coded signals by a matching filter ofeach receiver which is used for receiving the array elements; reconfiguring covariance matrix of signal data subjected to matching filtering; performing unitary transformation on the reconfigured covariance matrix to obtain the covariance matrix of a real number field; performing singular value decomposition on the covariance matrix of the real number field; estimating emission angles and acceptance angles of a plurality of objects by utilizing actual value combination spinning invariant factor; and realizing multi-target location according to a cross point of the two angles to obtain the position of a space object. According to the method, the combination spinning invariant factor is adopted to reconfigure the receiving data so as to improve the estimation performance of an object; and the covariance matrix of the real number field is obtained through unitary transformation, and characteristic decomposition is performed on the covariance matrix of the real number field so as to be favorable for real-time processing and realization on hardware.

The invention discloses a MIMO radar antenna array sparse arraying method, which is based on almost difference sets and difference bases, and establishes a MIMO radar transmitting/ receiving array rapidly through enumeration shifting process. When all transmitting array elements transmit orthogonal signals simultaneously and receiving array elements receive echo signals simultaneously, a virtual array with even space can be established equivalently by utilizing a phase center approximation principle; number of the transmitting/ receiving array elements is given, the continuous aperture maximization of the equivalent virtual array can be realized according to the MIMO radar antenna array sparse arraying method, thereby improving spatial resolution of a MIMO radar system significantly; and the continuous apertures of the virtual array are given, and the minimization of number of the transmitting/ receiving array elements can be realized according to the MIMO radar antenna array sparse arraying method, thereby reducing hardware cost of the system significantly. The MIMO radar antenna array sparse arraying method has small computational complexity, and is applicable to establishment of MIMO radar sparse linear arrays and planar array.