Abstract: An antenna assembly and related methods are described. The antenna assembly (1) comprises an extendible mast (2) constructed and arranged so as to be configurable between a coiled form and an extended form. The extended mast (2) is resiliently biased in the form of an elongate tube having a slit along its length. The coiled mast is wound about an axis extending transversely to the longitudinal extent of the mast. An antenna (6) is integrally coupled to the mast such that when extended, the mast supports and positions the antenna, and when coiled, the mast and antenna are coiled together.

Abstract: Reconfigurable antennas are provided. A reconfigurable antenna includes a plurality of antenna radiators and a plurality of feeds that are electrically or electromagnetically coupled to the plurality of antenna radiators. The plurality of feeds control current or voltage of the plurality of antenna radiators. Related methods of operating a reconfigurable antenna are also provided.

Abstract: A method and apparatus are disclosed for improving RFID coverage using an antenna array having an adaptive antenna beam. The apparatus includes an RFID reader including an antenna array having a plurality of antenna elements. Subsets of the plurality of antenna elements are selectively activating in order to direct an antenna beam to communicate with at least one RFID tag. The method includes transmitting an interrogation signal from an antenna array by activating one or more subsets of a plurality of antenna elements forming the antenna array. In this way, the interrogation signal is directed thereby improving antenna coverage.

Abstract: An antenna system includes a first transmission line, a second transmission line, a third transmission line, a fourth transmission line, a first dipole antenna, a second dipole antenna, a third dipole antenna, a fourth dipole antenna, a fifth dipole antenna, a sixth dipole antenna, a seventh dipole antenna, and an eighth dipole antenna. Each dipole antenna is coupled through a corresponding transmission line to a feeding point. Each of the fifth dipole antenna, the sixth dipole antenna, the seventh dipole antenna, and the eighth dipole antenna is positioned between the feeding point and a corresponding one of the first dipole antenna, the second dipole antenna, the third dipole antenna, and the fourth dipole antenna. Each of the partial dipole antennas includes a positive radiation branch and a negative radiation branch. The angle between the positive radiation branch and the negative radiation branch is less than 100 degrees.

Abstract: An antenna includes a first radiating array coupled to the mast and a second radiating array coupled to the mast. Each of the first and second radiating arrays comprises a plurality of dipoles associated with a radiation frequency, each dipole coupled to the mast by a standoff. The two arrays are mounted approximately opposite to each other relative to the mast, rather than one array on top of the other array. The antenna may be part of a Positive Train Control (PTC) system and be disposed in proximity to a train track.

Abstract: An antenna for wireless apparatus which is placed in the vicinity of a conductive object is disclosed. The antenna for wireless apparatus includes a GND plate, a conductive plate parallel to the GND plate, two antenna elements, and two raising conductive plates. Each of the antenna elements includes a short-circuit conductive body and a radiation plate placed at an edge of the short-circuit conductive body. The two antenna elements are placed substantially parallel to a side surface of the conductive object with a distance of a half wavelength of a radio wave to be transmitted and received. The two raising conductive plates are placed close to the two antenna elements respectively and raise the conductive plate from the GND plate to a predetermined height.

Abstract: Antenna arrangement for a multi radiator base station antenna, the antenna having a feeding network based on air filled coaxial lines (15; 19), wherein the coaxial line being an integrated part of a back side of an antenna reflector (1), and wherein the coaxial line comprises an outer conductor (9) and an inner conductor (7; 14). Two parallel columns of radiators (11) are placed on a front side of the antenna reflector (1), the radiators (11) being fed from said feeding network.

Abstract: Antenna arrangement for a multi-radiator base station antenna, the antenna having a feeding network based on air filled coaxial lines (1, 2, 3), wherein each coaxial line comprises an outer conductor (8) and an inner conductor (4, 5, 6), wherein an adjustable differential phase shifter including a dielectric part (9) is arranged in the antenna and said dielectric part being movable longitudinally in relation to at least one coaxial line 1, 2, 3).

Abstract: The invention relates to the locating and identifying of objects with radiofrequency communication by inductive coupling, without electrical contact, between a reader and a tag. The device includes an array of N fixed RFID markers of RFID tag type, with inductive antennas placed at known positions, N being an integer greater than 1 and an RFID tag reader provided with a fixed reading inductive antenna passing in proximity to the N markers. The position of the N markers with respect to the inductive reading antenna is such that the mutual inductance between the inductive antenna of any marker and the inductive reading antenna is zero when no object to be located is present in the vicinity of the array of markers, and nonzero when an RFID tag is present in the vicinity of the marker considered. A coupling is established in the presence of a mobile tag in proximity to a marker.

Abstract: An unbalanced antenna includes a non-conductive substrate having one short edge, and two long edges connected respectively to two opposite ends of the short edge and parallel to each other, and an unbalanced antenna disposed proximate to the short edge of the non-conductive substrate and having a ground portion. A ground plane has side edges extending along the long edges of the non-conductive substrate, and is electrically coupled with the ground portion. The length of the ground plane is longer than a quarter of an equivalent wavelength corresponding to an operating frequency of the unbalanced antenna. A pair of choke sleeve structures are symmetrically disposed at opposite sides of the ground plane and spaced apart from the unbalanced antenna by a quarter of an equivalent wavelength corresponding to the operating frequency. Each choke sleeve structure has one end connected to the ground plane, and the other end extending in a direction away from the unbalanced antenna.

Abstract: The present invention provides a substrate type antenna capable of realizing high gain enhancement and high band enhancement in a simple configuration. In the substrate type antenna, a loop-like first joint pattern whose one spot is divided, is formed in one substrate surface of a substrate made of a dielectric material. Antennas are respectively connected to both end terminals of the first joint pattern at a position where the first joint pattern is divided. A loop-like second joint pattern formed at a position corresponding to the first joint pattern and whose one spot is divided, is formed in the other substrate surface of the substrate. A loop-like third joint pattern which is substantially concentric with the first joint pattern and which is formed at a position corresponding to the second joint pattern and whose spot is divided, is formed in the one substrate surface of the substrate.

Abstract: A multi-band dipole antenna includes spaced part first and second radiator sections, first and second mirroring radiator sections, and a balun, which are disposed on a substrate. The first mirroring radiator section is symmetrically disposed with respect to the first radiator section and is spaced apart from the first radiator section. The first radiator section and the first mirroring radiator section cooperate to resonate in a first frequency band. The second radiator section cooperates with the second mirroring radiator section to resonate in a second frequency band.

Abstract: A folded dipole antenna capable of transmitting and receiving signals from CDMA 450 system comprises a folded dipole Printed Circuit Board (PCB) having conducting strips on each side of the PCB forming excitation and grounding arms of the antenna, having a symmetric conducting strip configuration. The conducting strip on each side of the PCB includes an m-shaped conducting strip having a center conducting leg, and two symmetrically configured folded arms. The center conducting leg is thinner in width than the two folded arms. The PCB is placed is mounted perpendicularly to a base plate through a plastic holder. A coaxial cable having a center core extended through the folded dipole PCB connects with the excitation arm and with a metal shield soldered along the center conducting leg of the ground arm.

Abstract: The present invention provides a donor antenna comprising a base plate having a top surface and a bottom surface; an array of folded dipole antenna mounted on the top surface of the base plate through a plastic holder, wherein the array of folded dipole antennas are arranged in a lattice form; and a feed network defining on the bottom surface for electrically connecting the array of folded dipole antennas to collectively feed to a connector; wherein each of the folded dipole antenna comprises a substrate having symmetrically configured conducting strips defined on the both side of the substrate forming an excitation arm and a ground arm of the folded dipole antenna.

Abstract: An antenna arrangement comprising an input/output connection and a first and a second tuning network with different transfer functions. The arrangement additionally comprises an antenna and a switch for connecting the input/output connection of the arrangement to one of said tuning networks, with a second switch for connecting the antenna of the arrangement to the tuning network to which the input/output connection of the arrangement has been connected. The arrangement comprises a sensor for sensing a form factor of the arrangement or of an apparatus in which the arrangement is used, and said sensor can be used for influencing said first and second switches, so that a device which has been connected to the arrangement may be connected to the antenna via a tuning network optimal for the current form factor of the arrangement.

Abstract: The present invention provides a donor antenna comprising a base plate having a top surface and a bottom surface; an array of folded dipole antenna mounted on the top surface of the base plate through a plastic holder, wherein the array of folded dipole antennas are arranged in a lattice form; and a feed network defining on the bottom surface for electrically connecting the array of folded dipole antennas to collectively feed to a connector; wherein each of the folded dipole antenna comprises a substrate having symmetrically configured conducting strips defined on the both side of the substrate forming an excitation arm and a ground arm of the folded dipole antenna.

Abstract: A multi-band dipole antenna includes spaced part first and second radiator sections, first and second mirroring radiator sections, and a balun, which are disposed on a substrate. The first mirroring radiator section is symmetrically disposed with respect to the first radiator section and is spaced apart from the first radiator section. The first radiator section and the first mirroring radiator section cooperate to resonate in a first frequency band. The second radiator section cooperates with the second mirroring radiator section to resonate in a second frequency band.

Abstract: A dual polarized variable beam tilt antenna having a superior Sector Power Ratio (SPR). The antenna may have slant 45 degree dipole radiating elements including directors, and may be disposed on a plurality of tilted element trays to orient an antenna boresight downtilt. The directors may be disposed above or about the respective dipole radiating elements. The antenna has a beam front-to-side ratio exceeding 20 dB, a horizontal beam front-to-back ratio exceeding 40 dB, a high-roll off, and is operable over an expanded frequency range.

Abstract: A feed module is provided for an array antenna. The feed module comprises a multi-layer printed circuit board (PCB) feed structure for coupling signals between connections to transmitters or receivers and connection points for connecting to antenna elements of the array antenna. The multi-layer PCB feed structure comprises a body portion, incorporating coupling components, and a number of line sections for connecting to elements of the array antenna. The planar layers of the multi-layer PCB are arranged to be mounted substantially perpendicular to a planar array of antenna elements of the array antenna when the feed module is integrated therewith.

Abstract: A phased-array antenna panel for a super economical broadcast system is provided. The phased-array antenna panel system includes an antenna panel support member, a first pair of striplines and a second pair of striplines. The antenna panel support member includes a front reflector surface to support first and second columns of constantly-spaced, crossed-dipole radiators, a first pair of signal ground cavities disposed beneath the first column of crossed-dipole radiators, a second pair of signal ground cavities disposed beneath the second column of crossed-dipole radiators, and a rear surface including first and second pairs of signal distribution cable connectors. The first pair of striplines are respectively disposed within the first pair of signal ground cavities and are coupled to the first pair of signal distribution connectors and the first column of crossed-dipole radiators.

Abstract: In one embodiment, the present invention is a dual-polarized antenna array constructed from first and second instances of a planar antenna that are co-located and orthogonal to one another. The planar antenna comprises three conducting elements and a transmission line. The first conducting element comprises a straight segment and two arms of equal length. The proximal ends of the two arms are attached to opposite ends of the straight segment. The arms extend away from the second and third conducting elements and towards one another. The second and third conducting elements are separated by a gap and together form a mirror image of the first conducting element. The transmission line has first and second conductors that are coupled to the second and third conducting elements, respectively. In another embodiment, the present invention is a tri-polarized antenna array constructed from three orthogonal co-located instances of the planar antenna.

Abstract: The replacement and elimination of duplexers in a tightly coupled dipole phased array starts with transmit and receive functions physically separated and having different antenna port feeds. The simple coupling network used with tightly coupled dipole arrays is replaced by a state switch which alternates between a coupling state and a dipole feed connection state. The basic method can be applied to antenna apertures of various kinds, including both linear and dual polarized versions. The ability to locate state switches at various nodes in tightly coupled dipole phased arrays permits flexibility in antenna design and eliminates bulky and lossy components, simplifies the design requirements and allows independent optimization of the components.

Abstract: The utilization of small antennas for mobile devices and for low frequency (long wavelength) applications is desired. Further, efficient use of transmission power is desirable, especially in mobile applications. For this purpose, a system is provided that includes one or more of: a multiple-resonator transmitter/receiver, a high bandwidth electrically small antenna, a resonator with a variable feed location, a resonator with a variable reactive component load, and a method for estimating a resonator system response to a component configuration and selected excitation.

Abstract: The present invention provides a chassis for a radio frequency communication device. The chassis includes an electrically conductive chassis portion having a length and a width, where the electrically conductive chassis portion has a line of symmetry substantially centered widthwise and running along the length of the electrically conductive chassis portion. The chassis further includes an electrically conductive bridge, which has a first end coupled to the electrically conductive chassis portion for enabling a current to pass therebetween. The chassis still further includes a path conductor having a first end and a second end, and a length therebetween. The first end of the path conductor is coupled to the electrically conductive chassis portion at an asymmetrical location relative to the line of symmetry.

Abstract: A tire air pressure monitoring system has a plurality of sensor units and a receiver. The pressure sensor units are mounted near corresponding tires to measure tire air pressures and transmit transmission signals indicating the respective measured tire air pressures. The receiver has an antenna element, a variable capacitor and a power supply source. The variable capacitor is coupled to the antenna element. The power supply source supplies electric power to the antenna element. The voltage supplied to the variable capacitor is controlled so that a current flowing in the antenna element is changed and its directivity is changed. Thus, the transmission signals will be received more surely.

Abstract: The invention provides an improved array antenna, an array antenna system and an improved method for utilizing the improved array antenna and array antenna system. This is accomplished by an array antenna comprising a region of reference potential, e.g. a ground plane, and a spatially extended collection of at least two antenna elements capable of being at least partly balanced driven and at least partly unbalanced driven. The antenna elements have a first radiating element connected to a first port and a second radiating element connected to a second port. In other words, the antenna element has at least two ports. The radiating elements are arranged substantially adjacent and parallel to each other so as to extend at least a first distance approximately perpendicularly from said region of reference potential.

Abstract: A communication system, including a transmitter having a transmitting circuit unit to generate a data transmission-adaptive RF signal and an electric-field-coupling antenna to send out the RF signal as an induction field and/or an electrostatic field, a receiver having a electric-field-coupling antenna and a receiving circuit unit to receive and process the RF signal received by the electric-field-coupling antenna, and a coupling apparatus having a plurality of transmitter-side electric-field-coupling antennas to receive the RF signal which is in capacitive coupling with the transmitter-side electric-field-coupling antenna and outputted from the electric-field-coupling antenna, a signal line to transmit the received RF signal, and a plurality of receiver-side electric-field-coupling antennas to output the RF signal which is in capacitive coupling with said the receiver-side electric-field-coupling antenna and transmitted through the signal line.

Abstract: An antenna is provided for operating within the electrically small antenna regime (i.e., ka?0.5), and having bandwidth performance quite close to fundamental limits. The antenna of the invention, in various embodiments, is based upon spherical resonator structures that are characterized by a performance factor (Q/Qchu,) close to 1.5. The antenna combines a resonator structure determined according to the method of the invention with an appropriate transmission line feeding arrangement, such that the resonator effectively couples the transmission line mode to the radiating spherical harmonic mode in an impedance-matched manner.

Abstract: An antenna design, having two symmetrical phased array blade antenna elements which provide improved lateral target coverage with an increased effective radiated power and exhibits smooth null-free unidirectional antenna patterns. The direction of the unidirectional antenna pattern is dictated by a switching command under control of a user. Each blade antenna element is coupled to a 90-degree hybrid coupler and an RF switching device by a semi-rigid RF cable. Each blade antenna element is also connected to a sub-resonant choke balun for improved impedance matching and resultant distortion-less antenna patterns.

Abstract: The invention proposes a method for controlling a variable of transmission between a mobile network element and a fixed network element, wherein the transmission is effected by repeatedly sending of data units, and a control of the variable of the transmission based on a target data unit error rate is performed, the method comprising the steps of detecting (S2), whether a received data unit includes an error, analyzing (S3), in case an error is detected, the transmission number of the data unit, detecting (S4), whether the analyzed diversity of the data unit is equal to a target transmission number, and forwarding (S5) the data unit to a network control element in case the transmission number of the data unit is equal to the target transmission number, or in case no error is detected. The invention also proposes a corresponding fixed network element and a corresponding network control element.

Abstract: A cassette device includes a radiation detecting cassette having a radiation detector therein for detecting radiation having passed through a subject and converting the detected radiation into radiation image information, a transmission and reception controller connected to the radiation detector for transmitting the radiation image information to an image processor by way of wireless communications, and a cassette storage bag for storing the radiation detecting cassette therein. The cassette storage bag includes an antenna incorporated therein for transmitting the radiation image information from the transmission and reception controller to the image processor by way of wireless communications. The transmission and reception controller and the antenna are capable of being electrically connected to each other through detachable connectors.

Abstract: Systems and methods for communicating over multiple frequency bands include a driven antenna element and a parasitic element communicatively coupled to the driven antenna element, the parasitic element including at least a first and a second conductive section. The parasitic element can include two or more conductive sections, and the sections can be coupled using a connector (e.g., switching element or trap). Further, some driven antenna elements may be associated with two or more parasitic elements.

Abstract: A vertically polarized traveling wave antenna forms peanut-type directional lobes without significant nulls between the lobes. A self-supporting coaxial line feeds quad-dipole bays coupled around the coaxial line, with opposed dipole pairs spaced along the coaxial line. Matched-layer spacing provides substantial cancellation of the reactive components of the loads. Dipoles are oriented parallel to the coaxial line axis, with opposite “hot” (center coupled) elements oppositely oriented. Radiated signals have rotating phase. Changing the spacing within quads from a quarter wavelength or rotating the second dipole pair of each quad away from a right angle causes the antenna to radiate strongly on one axis and weakly at right angles thereto, without the nulls of back-to-back panel antennas.

Abstract: An antenna design, having two symmetrical phased array blade antenna elements which provide improved lateral target coverage with an increased effective radiated power and exhibits smooth null-free unidirectional antenna patterns. The direction of the unidirectional antenna pattern is dictated by a switching command under control of a user. Each blade antenna element is coupled to a 90-degree hybrid coupler and an RF switching device by a semi-rigid RF cable. Each blade antenna element is also connected to a sub-resonant choke balun for improved impedance matching and resultant distortion-less antenna patterns.

Abstract: Techniques are provided herein for generating multiple radiation patterns. An antenna system comprises an antenna array having one or more antennas for providing a first radiation pattern and a second radiation pattern, a transform matrix for transforming one or more inputs into one or more outputs according to a transform function, wherein the outputs of the transform matrix provide signals to the antennas with predetermined phases and magnitudes for generating the first and second radiation patterns, and a transmitter for providing a first set of signals corresponding to the first radiation pattern and a second set of signals corresponding to the second radiation pattern to inputs of the transform matrix.

Abstract: Methods and systems for generating and imaging THz electromagnetic radiation using a composite dipole array made up of novel structures of non-linear dipole strings with dual frequency resonances for frequency up conversion and frequency down conversion are disclosed. THz electromagnetic radiation resulting from the frequency down conversion process can be used as an illumination source for imaging, as a carrier for communications, or as an energy source for spectroscopy, for example. Optical electromagnetic radiation resulting from the frequency up conversion process can be used to form images from THz electromagnetic radiation for contraband detection, guidance systems, and medical applications, for example.

Abstract: A broadband composite dipole array (CDA) includes an array of macro dipoles on a non-conducting substrate adapted to receive radiation at two frequencies. Each macro dipole is an array of micro dipoles adapted to receive radiation at substantially the mean of the two frequencies. The micro-dipoles are coupled to each other by a parallel resonant circuit including a nonlinear element, wherein the minimum impedance of the circuit is a substantially short circuit at the difference frequency f1-f2, and the circuit has a substantially open circuit impedance in the range of frequencies from f1 to f2. The micro dipoles resonate efficiently at both frequencies f1 and f2 with low-loss. The nonlinear element in the resonant circuit generates a signal at the difference frequency which is the resonant frequency of the macro dipole antenna.

Abstract: Disclosed is an antenna device having a substrate, an antenna element for transceiving a wireless signal, an antenna signal feeding line for feeding the wireless signal, and an ion-implanted resonant pattern, which includes a first coupling pattern implanted in the substrate by an Ion-implantation process and a second coupling pattern formed at a position corresponding to the first coupling pattern with a predetermined distance therebetween, formed at an adjacent position with respect to the antenna element. As the antenna element transceives the wireless signal of the predetermined radiation frequency and generates an induction voltage, the first coupling pattern and the second coupling pattern each generates a coupled induction voltage and a capacitance therebetween, hence forming a resonance with the antenna element.

Abstract: An antenna device includes: a plurality of element arrays; a mast member which holds the plurality of element arrays such that the element arrays are arranged in a direction perpendicular to a reference plane; and a first feeding circuit which feeds the element arrays, wherein each element array comprises: a predetermined number of dipole antennas; and a second feeding circuit which feeds the predetermined number of dipole antennas such that the predetermined number of dipole antennas can transmit and/or receive predetermined circularly polarized wave components alone, for each of the element arrays, the first feeding circuit and the second feeding circuit of the element array are connected through an independent transmission path, and each element array is fed with a predetermined phase difference.

Abstract: A multi-antenna receiving and processing circuit assembly is disclosed to include multiple antennas for receiving wireless signals, multiple pre-processing units respectively electrically connected to the antennas, a matching circuit electrically connected to the pre-processing units for matching signals from the pre-processing units into a matching signal, a post-processing unit electrically connected to the matching circuit for processing the matching signal from the matching circuit through a single intermediate frequency signal and into a plurality of audio frequency signals respective to each antenna, and an output circuit electrically connected to the post-processing unit for outputting the audio frequency signals to external audio output devices.

Abstract: An antenna minimizes radiation from the outer conductor (44) of a coaxial cable (40) that is coupled to the antenna by providing a balancing tab (90) that lies near the connection (72) of the cable outer conductor (44) to the antenna. One antenna includes a Yagi structure (12) constructed of a plate of metal that forms a long boom (20) and a plurality of directors (28) extending laterally across the boom, with an electrical coupling loop mounted at a rear region of the Yagi structure. The coupling loop includes a folded dipole in the form of a metal coupling plate that forms a loop (54) with a gap (70), the loop having a laterally elongated front loop end (60). The Yagi structure is formed with a balancing tab (90) that lies forward of the loop, that has a lateral length (D) less than half that of one of the directors, and that extends from only one side (22) of the boom which is the side to which the outer coax conductor (44) is connected to the loop.

Abstract: An antenna design, having two symmetrical phased array blade antenna elements which provide improved lateral target coverage with an increased effective radiated power and exhibits smooth null-free bi-directional antenna patterns. Each blade antenna element is coupled to a 180 degrees hybrid divider/combiner by a semi-rigid RF cable. Each blade antenna element is also connected to a sub-resonant choke balun for improved impedance matching and resultant distortion-less antenna patterns.

Abstract: First, second, third and fourth dipole antennas (14, 16, 18, 20) are disposed in a casing (1). The first through fourth dipole antennas are arranged in the same plane, and are disposed in line symmetry with respect to first through fourth imaginary lines (A, B, C, D) passing through the center of the casing (1) at an angle of 45 degrees between adjacent imaginary lines.

Abstract: A high-frequency two-dimensional antenna includes a plurality of dual-frequency antennas configured to receive signals having first and second frequencies above the microwave band of the electromagnetic spectrum. The dual-frequency antennas of the two-dimensional antenna are arrayed to an effective length to re-radiate signals at a third frequency, which is down-converted from the first and second frequencies. Each dual-frequency antenna of the two-dimensional antenna includes a plurality of dipole antennas, and a plurality of nonlinear resonant circuits. The nonlinear resonant circuits interconnect the dipole antennas and are configured to permit re-radiation of signals having the third frequency over the effective length. A method of down-converting signals having at least first and second electromagnetic radiation frequencies is also provided.

Abstract: A phased array antenna includes a substrate, and an array of dipole antenna elements are on the substrate. Each dipole antenna element includes a medial feed portion, and a pair of legs extending outwardly therefrom. Each dipole antenna element further includes a passive load, and a switch connected thereto for selectively coupling the passive load to the medial feed portion so that the dipole antenna element selectively functions as an absorber for absorbing received signals while the passive load dissipates energy associated therewith.

Abstract: A dual frequency antenna includes a plurality of dipole antennas configured to receive first and second frequencies. The antennas are arrayed to an effective length to reradiate at a third frequency, which is down-converted from the first and second frequencies. A plurality of nonlinear resonant circuits interconnect the plurality of dipole antennas and are configured to permit reradiation of the third frequency over the effective length through its low frequency dipole resonance. A method of down-converting at least first and second electromagnetic radiation frequencies is also provided. The method includes transmitting first and second electromagnetic beams at first and second frequencies, respectively. The first and second frequencies are converted to the difference frequency through a nonlinear resonant circuit coupling the at least two dipole antennas.

Abstract: A two-dimensional dual-frequency antenna array includes a plurality of dual-frequency antenna array elements configured to receive signals having first and second frequencies. The array elements of the two-dimensional antenna array may be structured to have half-wave dipole resonances—both at the mid-frequency of the two beams, merged to form the interference field, and also at the difference frequency, down converted from the first and second frequencies. Each individual dual-frequency antenna of the two-dimensional antenna array includes a plurality of dipole antennas, array elements, a plurality of nonlinear resonant circuits. The nonlinear resonant circuits interconnect the dipole antennas and are configured to permit re-radiation of signals having the third (difference) frequency in the form of resonant dipole radiation (resonant at the difference frequency).

Abstract: A high-frequency imaging system for the millimeter and submillimeter radiation includes a high frequency lens to image an object at its focal plane. The object emits electromagnetic radiation at a first frequency above the microwave band of the electromagnetic spectrum. A local oscillator generates an electromagnetic beam at a second frequency to illuminate a plurality of dual-frequency antennas at the focal plane of the lens. Intermodulation of first and second frequencies generates a signal distribution of a third frequency over the focal plane, which represents an image. Also, a method of providing an image at the third frequency of an object emitting electromagnetic radiation at a first frequency is provided. The method includes imaging the electromagnetic radiation at the first frequency from each point of the object onto the focal plane. An electromagnetic beam is transmitted to illuminate all elements of the focal plane array.

Abstract: An antenna assembly for wireless communications has various components to minimize signal influence when transmitting signals to minimize undesirable loop formation phenomena caused by (positive) feedback of signals. Signal wave scattering and diffraction causing back lobe radio frequency (RF) patterns are minimized by a particular antenna assembly structure having a reflector and at least one attenuating structural member, a metallic mesh wrapping the power cable of a feeder, a non-conductive antenna support structure, or any combination thereof. The dimensions of the various components, in particular the reflector and attenuators, can be varied according to desired wireless communications environment.

Abstract: An antenna system with at least one tunable dipole element with a length adjustable conductive member disposed therein that enables the antenna to be used over a wide range of frequencies. The element is made of two longitudinally aligned, hollow support arms made of non-conductive material. Disposed longitudinally inside each element is a length adjustable conductive member electrically connected at one end. In the preferred embodiment, each conductive member is stored on a spool that is selectively rotated to precisely extend the conductive member into the support arm. The support arms, which may be fixed or adjustable in length, are affixed at one end to a rigid housing. During use, the conductive members are adjusted in length to tune the element to a desired frequency.