618results about "Logperiodic antennas" patented technology

The present invention provides systems and methods for the evaluation of the urethra and periurethral tissues using an MRI coil adapted for insertion into the male, female or pediatric urethra. The MRI coil may be in electrical communication with an interface circuit made up of a tuning-matching circuit, a decoupling circuit and a balun circuit. The interface circuit may also be in electrical communication with a MRI machine. In certain practices, the present invention provides methods for the diagnosis and treatment of conditions involving the urethra and periurethral tissues, including disorders of the female pelvic floor, conditions of the prostate and anomalies of the pediatric pelvis.

An apparatus and method using a front internal dual band television antenna or a pair of internal dual band antennas for a portable entertainment module having a housing and a display screen. A front spiral antenna is embedded in the housing around the periphery of the display screen and is tuned to compensate for the influence nearby components. A rear logo-periodic antenna is located inside the rear of the housing and is modified to have various environmental openings to fit around existing components, vents and structures in the housing. Any pair of different antenna architectures could be used.

An antenna system that includes a directional antenna designed to reduce the occurrence of side lobes, thus reducing the possibility of interference with other radio frequencies is disclosed. The directional antenna includes an antenna member and a reflecting tube. The reflective tube is sleeved over the antenna member. The reflective serves to block unwanted radial side lobes. The directional antenna can also include provisions that assist in suspending the antenna member within the reflective tube.

The present invention relates to a source-antenna for transmitting / receiving electromagnetic waves comprising an array of n radiating elements (113, 114) operating in a first frequency band, means (20) with longitudinal radiation operating in a second frequency band, the array and the means with longitudinal radiation having a substantially common phase centre, the n radiating elements being arranged symmetrically about the longitudinal-radiation means, and each element (113, 114) of the array consisting of a radiating element of the travelling wave type.

A dual polarized variable beam tilt antenna (10) having a plurality of offset element trays (12) each supporting pairs of dipole elements (14) to orient the dipole element pattern boresight at a downtilt. The maximum squint level of the antenna is a consistent downtilt off of boresight and which is at the midpoint of the antenna tilt range. The antenna provides a high roll-off radiation pattern through the use of Yagi dipole elements configured in this arrangement, having a beam front-to-side ratio exceeding 20 dB, a horizontal beam front-to-back ratio exceeding 40 dB, and is operable over an expanded frequency range.

The present invention provides systems and methods for the evaluation of the urethra and periurethral tissues using an MRI coil adapted for insertion into the male, female or pediatric urethra. The MRI coil may be in electrical communication with an interface circuit made up of a tuning-matching circuit, a decoupling circuit and a balun circuit. The interface circuit may also be in electrical communication with a MRI machine. In certain practices, the present invention provides methods for the diagnosis and treatment of conditions involving the urethra and periurethral tissues, including disorders of the female pelvic floor, conditions of the prostate and anomalies of the pediatric pelvis.

The present invention relates to an electromagnetic wave transmission / reception source for a multireflector antenna of the Cassegrain type comprising longitudinal-radiation means operating in a first frequency band and an array of n radiating elements of the travelling-wave type operating in a second frequency band with the n radiating elements arranged symmetrically around the longitudinal-radiation means, the array and the longitudinal-radiation means having an approximately common phase centre, the array of n radiating elements being excited by a waveguide of polygonal cross section. The invention applies especially in satellite communication systems operating in the C-, Ku- or Ka-bands.

An antenna device includes a substrate, and a radiating element disposed on the substrate. The radiating element has two spiral arms unfurling in an Archimedean progression and terminating in a logarithmic progression. The substrate is formed from a dielectric material and includes multiple perforations for providing passage of coolant through the substrate. The radiating element is disposed on a front surface of the substrate, and an enclosure is formed on a rear surface of the substrate to provide a reflective cavity for reflecting radiation to the front surface of the substrate. The enclosure includes a hexagonal perimeter formed by a wall. The antenna device may be used as an element in a planar phased array.

A micro-helix antenna. The antenna comprises a helically-shaped conductive element disposed on a dielectric core. The diameter of the helix formed by the conductive element is very small relative to the wavelength of the antenna, preferably no more than about 1 / 100th of the wavelength. Having such a small diameter, this micro-helix antenna can be further compressed into two- and three-dimensional shapes, such as spirals, helices and meandering or stochastic patterns. The micro-helix antenna can be created by pressing a fine wire into a helical shape. Alternately, the helical conductor can be formed by a laser ablation process or laying down the helical shape using a direct-write process.

A helical antenna has a helix supported by a helix support. The helix support includes at least one piece of flexible sheet having its two surfaces covered with a layer antistatic material. The flexible sheet is curlable into a revolution surface configuration to form a revolution surface-shaped support section for at least partially supporting a portion of the helix component there around. A grounding mechanism electrically grounds the external sheet surface to the helix and the two sheet surfaces to one another when in the revolution surface configuration while a locking mechanism locks the flexible sheet in the revolution surface configuration. The combination of the helix and the flexible support renders the antenna structurally relatively rigid in all directions.

RF and microwave radiation directing or controlling components are provided that may be monolithic, that may be formed from a plurality of electrodeposition operations and / or from a plurality of deposited layers of material, that may include switches, inductors, antennae, transmission lines, filters, and / or other active or passive components. Components may include non-radiation-entry and non-radiation-exit channels that are useful in separating sacrificial materials from structural materials. Preferred formation processes use electrochemical fabrication techniques (e.g. including selective depositions, bulk depositions, etching operations and planarization operations) and post-deposition processes (e.g. selective etching operations and / or back filling operations).

The invention discloses a helical antenna with a small reflection surface, aiming at improving the helical antenna gain, enlarging the launching coverage range of a launcher and meeting the long-distance communication requirement of a tire pressure monitor system (TPMS). The helical antenna comprises a body and the reflection surface, wherein the body has a spiral structure formed by winding a metal wire or a metal tube, and is a normal mode helical antenna; and the reflection surface is arranged under the body and is connected with a negative pole or a ground wire of a feeding point of the body. The reflection surface meets the condition that (D0-D) / 2 is more than or equal to A-x and less than or equal to A, wherein D is the screw diameter of the body, D0 is the diameter of the reflection surface, A and x are constants, x is more than 0 and less than A, A is more than x and less than or equal to 0.01 lambda, and lambda is the wavelength of a signal transmitted by the launcher within the free space.

Reconfiguration of parasitically controlled elements in a phased array is used to expand the range of operational functions. Embedded array elements can be frequency tuned, and bandwidth can be improved by using reconfiguration to broaden the bandwidth of the embedded elements. For high gain arrays, beam squint can be a limiting factor on instantaneous bandwidth. Reconfiguration can alleviate this problem by providing control of the element phase centers. Scan coverage can be improved and scan blindness alleviated by controlling the embedded antenna patterns of the elements as well as by providing control of the active impedance as the beam is scanned. Applying limited phase control to the elements themselves can alleviate some of the complexity of the feed manifold. A presently preferred method of designing reconfigurable antennas is to selectively place controlled parasitic elements in the aperture of each of the antenna elements in the phased array. The parasitic elements can be controlled to change the operational characteristics of the antenna element. The parasitic elements are controlled by either switching load values in and out that are connected to the parasitic elements or are controlled by applying control voltages to variable reactance circuits containing devices such as varactors. The parasitic elements can be controlled by the use of a feedback control subsystem that is part of the antenna system which adjusts the RF properties of the parasitic components based on some observed metric. The controllable characteristics include directivity control, tuning, instantaneous bandwidth, and RCS.

An antenna includes at least one element whose physical shape is at least partially defined as a second or higher iteration deterministic fractal. The resultant fractal antenna does not rely upon an opening angle for performance, and may be fabricated as a dipole, a vertical, or a quad, among other configurations. The number of resonant frequencies for the fractal antenna increases with iteration number N and more such frequencies are present than in a prior art Euclidean antenna. Further, the resonant frequencies can include non-harmonically related frequencies. At the high frequencies associated with wireless and cellular telephone communications, a second or third iteration, preferably Minkowski fractal antenna is implemented on a printed circuit board that is small enough to fit within the telephone housing. A fractal antenna according to the present invention is substantially smaller than its Euclidean counterpart, yet exhibits at least similar gain, efficiency, SWR, and provides a 50Ω termination impedance without requiring impedance matching.

A dielectrically-loaded loop antenna with a cylindrical dielectric core, a feeder structure passing axially through the core, a sleeve balun encircling one end portion of the core and helical antenna elements extending from a feed connection with the feeder structure at the other end of the core to the rim of the balun. The antenna elements are arranged as a pair of laterally opposed groups of conductive elongate helical elements each having at least first and second conductive elements of different electrical lengths to form a plurality of looped conductive paths. By forming at least one of the conductive elements in each group as a conductive strip with one or both edges meandered, such that the edges of the strip are non-parallel and have different electrical lengths, additional modes of resonance arc created, yielding an improvement in bandwidth.

The invention relates to a small (0.5 wavelength or less) adaptable antenna system. In particular it relates to the use of loaded parasitic components in the antenna aperture for the purpose of controlling the RF properties of the antenna. Such an antenna system is here referred to as a controlled parasitic antenna (CPA). Parasitic elements within the radiating aperture are terminated by active (controllable) impedance devices. A feedback and control subsystem periodically adjusts the impedance characteristics of these devices based on some observed metric of the received waveform. Such antenna systems can provide multifunctionality within a single aperture and / or mitigate problems associated with the reception of an interfering signal (or signals) or multi-path effects. Such antenna systems are particularly suitable to a situation where an aperture size is desired that is too small for the use of an adaptive phased array.

In a helical antenna apparatus, a first variable capacitance element is connected between a first helical antenna element and a second helical antenna element, and a second variable capacitance element is connected between a first terminal of a balanced port of a balanced to unbalanced transformer and the first helical antenna element. A third variable capacitance element is connected between a second terminal of the balanced port of the balanced to unbalanced transformer and the second helical antenna element. A detector measures a detection voltage Vd corresponding to a reflected power of a reflected signal reflected from the first and second helical antenna elements when the first and second helical antenna elements are fed with a transmission signal from a radio transmitter, and an adaptive controller adaptively controls respective capacitance values of the first to third variable capacitance elements.

An antenna device comprising (a) a mounting substrate having a ground portion and a non-ground portion, (b) a chip antenna mounted onto said non-ground portion, which comprises a substrate, a first radiation electrode formed on said substrate, a power-supplying electrode connected or not connected to the other end of said first radiation electrode, and a terminal electrode connected or not connected to one end of said first radiation electrode, and (c) at least one second radiation electrode formed in a conductor pattern on said non-ground portion, said second radiation electrode having one end connected or not connected to said terminal electrode and the other end which is an open end, and a cavity existing between said chip antenna and / or said second radiation electrode and said ground portion.

An electrically small broadband antenna comprises a plurality generalized contrawound toroidal helical antenna elements, each made from a single continuous conductor divided into two length portions each of which are substantially the same length and which have a generalized helical pattern, wherein the helical pitch senses the two length portions are opposite to one another, and the two length portions are insulated from one another and overlap one another on the surface of a generalized toroid. Each antenna element incorporates a signal coupler with an impedance matching network, wherein the first ports of the plurality of signal couplers are in proximate location to one another and are connected together to a common signal input port, and the second ports of the respective signal couplers are connected to the respective signal feed ports at the node locations where the respective length portions join one another, or at a diametrically opposite location.

An antenna system including an antenna device and feed device for transmitting and receiving circularly polarized RF waves in a first mode of operation, and of linearly polarized RF waves in a second mode of operation, and a hand-held mobile communication device provided with such an antenna system. A radiating structure (10) including N helical radiating elements (12A-D), being coextending and coaxially arranged on a support structure (11) are fed in order to provide for transmission / reception of circularly polarized RF waves in the first mode of operation. N is an integer greater than one. Further, means (24A-D, 16, 17, 19, 25, 25A) are arranged for essentially uniform excitation of the helical radiating elements (12A-D) in order to provide for transmission / reception of linearly polarized RF waves in the second mode of operation.

A read-write processing apparatus communicates with an RFID tag provided with a semiconductor memory to exchange commands and responses through antenna coils. A condition under which only a carrier wave is transmitted is set prior to a communication with the RFID tag and a level from a reception signal obtained under this condition is extracted as noise level. The extracted noise level is displayed or outputted to an output host apparatus.

The invention relates to a multiband antenna structure suitable for mobile stations in particular. The radiating elements of the antenna include not only a helix (210) but also the joining piece (220) that attaches the helix to the apparatus. The helix is shaped such that the distance between its conductor turns varies. The electrical length of the joining piece is increased e.g. by means of a conductive projection (226) that remains within the covering of the apparatus. By suitably dimensioning the parts, at least five of the resonances that the helix and joining piece have together and separately are arranged at useful points on the frequency scale. The structure according to the invention is despite the several bands simple and relatively low in production costs.

An antenna device comprising (a) a mounting substrate having a ground portion and a non-ground portion, (b) a chip antenna mounted onto said non-ground portion, which comprises a substrate, a first radiation electrode formed on said substrate, a power-supplying electrode connected or not connected to the other end of said first radiation electrode, and a terminal electrode connected or not connected to one end of said first radiation electrode, and (c) at least one second radiation electrode formed in a conductor pattern on said non-ground portion, said second radiation electrode having one end connected or not connected to said terminal electrode and the other end which is an open end, and a cavity existing between said chip antenna and / or said second radiation electrode and said ground portion.

This invention relates to improved ultra-wideband synthetic aperture radar and inverse synthetic aperture radar, capable of simultaneously and independently imaging a plurality of spectral and polarimetric channels covering multiple radio frequency octaves. Advances in technologies relating to signal processing, graphical user interfaces, color representations of multi-spectral radar images, low aerodynamic drag polarimetric SAR antenna systems, and synthetic aperture radar aircraft platforms are some of the advancements disclosed herein.

A pseudo-fractal antenna is provided comprising a dielectric, and a radiator proximate to the dielectric having an effective electrical length formed in a pseudo-fractal geometry. That is, the radiator includes at least one section formed in a fractal geometry and at least one section formed in a non-fractal geometry. The antenna can be either a monopole or a dipole antenna. For use in a wireless communication telephone, the antenna operating frequency can be approximately 1575 megahertz (MHz), to receive global positioning satellite (GPS) information. In one aspect, the radiator has a fractal geometry section formed as a Koch curve. When the antenna is a dipole, the counterpoise can also be a pseudo-fractal geometry with a section formed in Koch curve fractal geometry section. The radiator can be a conductor embedded in the dielectric. Alternately, the radiator is a conductive line overlying a dielectric layer.