30 results about "Far field radiation pattern" patented technology

Methods and systems of tagging objects and reading tags coupled to objects. At least some of the illustrative embodiments are systems comprising a reading antenna, a tag reader coupled to the reading antenna, and a radio frequency identification (RFID) tag comprising a tag antenna electromagnetically coupled to the reading antenna. The RFID tag couples to an object such as the body of a living organism or a metallic article. Moreover, the tag antenna has a far-field radiation pattern in a direction away from the object that is substantially unaffected by proximity of the RFID tag to the object, and substantially unaffected by which surface of the RFID tag faces the object.

An active antenna array is arranged to activate subsets of switchable elements causing the antenna to form a first beam having a first beam pattern, and later to form a second beam having a second beam pattern of substantially identical far field radiation pattern to the first beam pattern but with different origins. A receiver receives radiation reflected from a target back to the antenna when the antenna is configured with the first beam pattern and then when configured with the second beam pattern, and compares the phase of the radiation received at the receiver when the antenna is configured with the first beam pattern with the phase of the radiation received at the receiver when the antenna is configured with the second beam pattern to provide a phase difference signal. A target locating means determines the angular location of the target from the phase difference signal.

The present invention belongs to the field of electromagnetic value computing, and particularly relates to a rapid and accurate analysis method for large-scale MIMO array antenna far-field radiation. The method comprises: determining a structural parameter of an M*N-element plane array antenna; computing a relationship between an incident field and a scattered field of an element antenna; according to mutual coupling characteristics among element antennas, selecting a sub-array form and size of an extraction unit on an array environment condition; for an antenna sub-array of the extraction unit, computing a unit far-field radiation pattern of the sub-array; and according to the unit far-field radiation patterns of the array and a superposition principle, computing an array antenna far-field radiation pattern. According to the invention, by utilizing the accuracy of mutual coupling computation, the problems that the use of such methods as the moment method, the finite element method and the finite difference time domain (FDTD) method are limited by computing capacity of a single computer, and when the scale of the array antenna is too large, rapid and accurate computation of the antenna radiation field cannot be implemented with a full wave simulation method because of large consumption of memory and computing time, are effectively solved. The method provided by the invention is capable of analyzing the radiation pattern of a large and conformal array antenna, and has higher synthesizing accuracy and higher analysis speed.

Disclosed is a system and method for determining the far-field radiation pattern of an antenna within a composite radiator. The method involves performing a near-field scan at an angular sample spacing corresponding to a minimum sphere centered at the crossing of two rotational axes encompassing the composite radiator, computing coefficients based on the near-field scan, adding a phase adjustment to the far field based on a translation from the scan origin to a point within the antenna, re-computing the coefficients, and truncating the re-computed coefficients, thereby retaining a number of coefficients corresponding to the diameter of a minimum sphere encompassing the antenna only. In doing so, the far-field radiation pattern of the antenna may be determined from the truncated set of coefficients with interference effects of the composite radiator substantially mitigated.

Provided is a system and method for measuring an antenna radiation pattern in a Fresnel region based on a phi-variation method. The system includes a rotator for changing angles of a reference antenna and a target antenna; a vector network analyzer for obtaining radiation pattern data in accordance with transmission/reception radio frequency (RF) signals between the reference antenna and the target antenna; a measurement unit for calculating a far-field radiation pattern based on the radiation pattern data received from the vector network analyzer; and a controller for controlling the rotator according to a measurement angle transmitted from the measurement unit.

The present invention discloses a conformal antenna array seeker modeling simulation method. The method comprises: S1. selecting rectangular microstrip patch antenna elements as directed radiation antenna elements of a conformal antenna array seeker, and performing location configuration on the rectangular microstrip patch antenna elements according to a shape of a seeker carrier platform, wherein a plurality of rectangular microstrip patch antenna elements form an antenna array; S2. applying a mathematical relationship of Euler rotation transformation to complete derivation of a far-field radiation pattern function of the conformal antenna array seeker; and S3. applying a genetic optimization algorithm to optimally design a far-field radiation pattern of the conformal antenna array seeker. By use of the method disclosed by the present invention, a radar diffusion cross section of the seeker can be reduced, an excellent electromagnetism stealth property is achieved, and the highest sidelobe value of the far-field radiation pattern is significantly improved.

Novel reconfigurable antennas are provided which may be used to accommodate the requirements for wideband multi-standard handheld communication devices. It is shown that using a shape memory alloy spring actuator, the height of a helical antenna and therefore the pitch spacing and angle can be varied. This can in turn tune the far-field radiation pattern and gain of the antenna dynamically to adjust to new operating conditions. The radiation pattern can further be directed using a two-helix array. Finally, a helical antenna embodiment is implemented and measured using a shape memory alloy actuator. Measurement results confirm that while keeping the centre frequency constant, gain tunability can be attained using this structure.

A method of making a low-loss electromagnetic wave resonator structure. The method includes providing a resonator structure, the resonator structure including a confining device and a surrounding medium. The resonator structure supporting at least one resonant mode, the resonant mode displaying a near-field pattern in the vicinity of said confining device and a far-field radiation pattern away from the confining device. The surrounding medium supports at least one radiation channel into which the resonant mode can couple. The resonator structure is specifically configured to reduce or eliminate radiation loss from said resonant mode into at least one of the radiation channels, while keeping the characteristics of the near-field pattern substantially unchanged.

A nanophotolithography mask includes a layer of an electrically conductive optically opaque material deposited on a mask substrate in which regular arrays of sub-wavelength apertures are formed. The plasmonic excitation in the layer perforated with the sub-wavelength apertures arrays under the light incident on the mask produces high resolution far-field radiation patterns of sufficient intensity to expose a photoresist on a wafer when propagated to the same. The fill-factor of the mask, i.e., the ratio of the total apertures area to the total mask area, may lead to a significant increase in mask manufacturing throughput by FIB or electron beam “writing”. The mask demonstrates the defect resiliency and ability to imprint coherent clear features of nano dimensions and shapes on the wafers for integrated circuits design.

The invention provides a laser radar orthogonal receiving and transmitting system based on a discrete adjustable grating. The laser radar orthogonal receiving and transmitting system comprises a transmitting unit and a receiving unit, wherein the transmitting unit transmits light wave signals in a specific far-field radiation pattern along a first direction, and scans in a second direction; the receiving unit receives an optical detection signal which is transmitted by the transmitting unit and is reflected by an object to be detected along the second direction, and scans in the first direction; and the first direction is perpendicular to the second direction, wherein the transmitting unit and/or the receiving unit comprise/comprises a surface grating array formed by a plurality of surface gratings. According to the laser radar orthogonal receiving and transmitting system, the surface grating array of the discrete adjustable grating is adopted to replace a continuous adjustable phased array grating, so that the laser radar orthogonal receiving and transmitting system is simple in structure.

The invention provides a laser radar orthogonal receiving and transmitting array. The laser radar orthogonal receiving and transmitting array comprises a transmitting unit and a receiving unit, wherein the transmitting unit transmits light wave signals in a specific far-field radiation pattern along a first direction, and scans along a second direction; the receiving unit receives an optical detection signal which is transmitted by the transmitting unit and is reflected by an object to be detected along the second direction, and scans along the first direction; the first direction is perpendicular to the second direction. The laser radar orthogonal receiving and transmitting array is based on the quadrature receiving and transmitting principle, the number of needed phase shifters can be reduced to a great extent, the production cost is reduced, the integration level can be improved, and the control difficulty of the laser radar quadrature receiving and transmitting array can be reduced.

A lens design method is disclosed for designing a lens to reshape an actual far-field radiation pattern of a radiation source, such as a spiral antenna, to a preferred far-field radiation pattern. The method comprises:—determining a preferred far-field radiation pattern of the radiation source;—deriving a corresponding near-field radiation pattern from the preferred far-field radiation pattern;—determining an actual near-field pattern of the radiation source;—mapping an electric field and a magnetic field of the actual near-field radiation pattern to the derived near-field radiation pattern using a transfer relationship, the transfer relationship comprising material parameters which characterize the lens; and,—determining the material parameters.

The invention provides a geological exploration radar. The geological exploration radar comprises a frequency reconfigurable antenna module used for receiving or sending signals of all frequency bands; and the frequency reconfigurable antenna module is made of a graphene material. By means of the reconfigurable antenna, the geological exploration radar can dynamically select different working modes according to the difference of environments, so that one antenna achieves the function of a plurality of antennas. With the geological exploration radar of the invention adopted, the problems of electromagnetic interference and system miniaturization can be effectively solved; and the frequency reconfigurable antenna based on the graphene material is adopted. The working frequency of the antenna has a continuous adjustable characteristic within a specific frequency band range, and other radiation characteristics such as far-field radiation patterns and polarization modes of the antenna are kept unchanged.

This document describes techniques and systems to generate a point-source model for simulating near-field effects from structures of an antenna. The techniques and systems generate, based on near-field values extracted from electromagnetic simulations, respective far-field radiation patterns for active elements and, in some cases, passive elements of the antenna array. The far-field radiation patterns account for electromagnetic interactions between the active elements and an antenna structure, which can include passive elements of the antenna array. The techniques and systems output the far-field radiation patterns, which are effective to simulate, using an asymptotic numerical method, electromagnetic interactions between the antenna array and at least one interaction structure. Using the described point-source model, engineers can quickly and accurately simulate electromagnetic interactions between the antenna array and the interaction structure for various configurations and applications of the antenna array.