3191 results about "Multiple frequency" patented technology

A dielectrophoretic display is shifted from a low frequency closed state to a high frequency open state via at least one, and preferably several, intermediate frequency states; the use of such multiple frequency steps reduces flicker during the transition. A second type of dielectrophoretic display has a light-transmissive electrode through which the dielectrophoretic medium can be viewed and a conductor connected to the light-transmissive electrode at several points to reduce voltage variations within the light-transmissive electrode.

An impedance model of tissue is useful for describing conductivity reconstruction in tissue. Techniques for determining and mapping conductivity distribution in tissue supply useful information of anatomical and physiological status in various medical applications. Electrical Impedance Tomography (EIT) techniques are highly suitable for analyzing conductivity distribution. Electrical characteristics of tissue include resistive elements and capacitive elements. EIT techniques involve passing a low frequency current through the body to monitor various anatomical and physiological characteristics. The system can interrogate at multiple frequencies to map impedance. Analytical techniques involve forward and inverse solutions to boundary value analysis to tissue characteristics.

The present invention provides a multi-band, multi-mode RFID tag that uses a single antenna structure and integrated circuit to provide asset location information at any stage of a supply chain. The unified tag design operates at multiple frequencies (or bands) using the antenna structure, for example, 125 kHz, 13.56 MHz, 915 MHz, and 2.45 GHz, and preferably operates electrostatically (at lower frequencies) and electromagnetically (ay higher frequencies). An on-chip frequency monitor in the integrated circuit automatically determines which frequency is present and derives a local clock for the tag's integrated circuit, which can vary in accordance with the frequency or which can be constant. Alternatively, a phase locked loop circuit can be used to derive a local clock signal modulated into the interrogation signal. On-chip matching and power extraction circuits derive power for the tag from the interrogation signal, which is preferably passive. Additionally, a receiver can receive data from the interrogation signal.

The invention discloses a dipole antenna of an RF chip, comprising two metal sheets, a feeder line and an earth wire, wherein two tabulate metal sheets are mutually parallel and are both provided with short circuit points which are respectively used for connecting the feeder line and the earth wire. The dipole antenna of the RF chip of the invention integrates novel artificial electromagnetic materials, thus the dipole antenna has abundant chromatic dispersion characteristics so as to form various radioactive modes, which not only can avoid fussy impedance matching network, but also can tune by adjusting a feeder line feeding and coupling mode, an earth wire accessing mode, the topological structure of metal microstructure, the position of metalizing through holes as well as the short circuit point position among the feeder line, the earth wire, an upper layer of sheet metal and a lower layer of sheet metal, thus providing great convenience for multiple frequency point impedance matching; meanwhile, the dipole antenna of the invention adopts a chip mode to fully utilize radiating area to approach to the Chu Limit antenna dimension limit principle, the construction of double chips also brings technical advantages for limiting electromagnetic wave and reducing effect on antenna operation by the outside.

The identification of low noise stimulation frequencies for detecting and localizing touch events on a touch sensor panel is disclosed. Each of a plurality of sense channels can be coupled to a separate sense line in a touch sensor panel and can have multiple mixers, each mixer using a demodulation frequency of a particular frequency, phase and delay. With no stimulation signal applied to any drive lines in the touch sensor panel, pairs of mixers can demodulate the sum of the output of all sense channels using the in-phase (I) and quadrature (Q) signals of a particular frequency. The demodulated outputs of each mixer pair can be used to calculate the magnitude of the noise at that particular frequency, wherein the lower the magnitude, the lower the noise at that frequency. Several low noise frequencies can be selected for use in a subsequent touch sensor panel scan function.

A dynamic equalization system 12 for use in audio reproduction systems. The apparatus includes a chirp tone generator 38 which produces a tone having multiple frequencies. The chirp tone is broadcast into the listening space 10 from a transducer 14. The broadcast chirp tone is monitored by a second transducer 22 at the listening position to produce a received chirp tone. The received tone and the original tone are compared in a coefficient computer 44 connected to a programmable equalizer 42. The equalizer 42 uses the signal from the coefficient computer to compensate for irregularities 47 in listening space 10 and transducer 14 to produce a substantially undistorted listening experience from source 28 in listening space 10. The first step of the method of the invention is generation of a chirp tone. The chirp tone includes multiple frequencies. The chirp tone is broadcast into the listening space from a transducer placed at the selected transducer position. The broadcast chirp tone is next monitored by a transducer at the listening position to produce a received chirp tone. The received tone is then compared to the generated chirp tone and differences noted. The differences are used to program an equalizer for correction of sound. The process is done for each position where a transducer is located. Finally, sound from a program source is routed through the equalizer to the transducers for a corrected sound.

A compact, agile polarization diversity, multiple frequency band antenna with integrated electronics for terrestrial terminal use in satellite communications systems is disclosed. The antenna includes an antenna feed having highly integrated microwave electronics that are mechanically and electromagnetically coupled thereto in a distributed arrangement so that diverse polarization senses having a low axial ratio and electronic switching control of the polarization senses is provided. The arrangement of the integrated distributed transceiver configuration enables the mechanical rotation of the orientation of a first transceiver for skew alignment while a second transceiver remains stationary relative to the antenna feed assembly. The first transceiver can be a high-band transmitter and receiver pair that supports linear polarization senses and the second transceiver can be a low-band transmitter and receiver pair that supports circular polarization senses. The antenna system presented is highly compact and offers improved polarization performance previously achievable by only larger devices.

An automatic atherectomy system uses the rotary burr at the tip of a catheter as a sensing device, in order to measure both the electrical conductivity and permittivity of the surrounding tissue at multiple frequencies. From these parameters it is determined which tissue lies in the different directions around the tip. A servo system steers the catheter tip in the direction of the tissue to be removed. In non-atherectomy applications the rotary tip can be replaced with any desired tool and the system can be used to automatically steer the catheter to the desired position. The steering is done hydraulically, by pressurizing miniature bellows located near the catheter tip.

In an exemplary embodiment, a phased array antenna comprises a bidirectional antenna polarizer and is configured for bidirectional operation. The bidirectional antenna polarizer may combine active implementations of power splitters, power combiners, and phase shifters. Furthermore, in another exemplary embodiment a bidirectional antenna polarizer has extensive system flexibility and field reconfigurability. In yet another exemplary embodiment, the bidirectional phased array antenna operates in “radar-like” applications where the transmit and receive functions operate in half-duplex fashion. Furthermore, in exemplary embodiments, the phased array antenna is configured to operate over multiple frequency bands and/or multiple polarizations.

The design of integrated circuits, i.e., semiconductor products, is made easier with a semiconductor platform having versatile power mesh that is capable of supporting simultaneous operations having different frequencies on the semiconductor product; e.g., higher frequency operations may be embedded as diffused blocks within the lower layers or may be programmed from a configurable transistor fabric above the diffused layers. Preferably the power mesh is located above the layers having the operations requiring the different frequencies, and may be fixed in an application set given to a chip designer or may be configurable by the designer her/himself. For example, to support high speed communications adjacent an embedded high speed data transceiver, the transistor fabric may be programmed as a data link layer having higher performance requirements than the rest of the integrated circuit. The data link layer may be connected to one of the localized grids of the versatile power mesh which may have an increased density and/or wider strap width of a power/ground grid. Additional decoupling capacitance can be embedded in the lower layers of the semiconductor product and/or can be programmed from the configurable transistors fabric.

A resource allocation method for use in a wireless ATM network comprises receiving on a wireless signaling channel a request for access to a shared frequency-time sliced wireless medium. A channel matrix is then searched for a set of available frequency-time slots. The channel matrix represents a time frame within the shared frequency-time sliced wireless medium, and is used to keep track of resource allocation in the time-frequency sliced medium. The set of available time-slots is then allocated if the allocation does not violate a frequency switching constraint, and if the set of available frequency-time slots contains a number of slots no smaller than a requested number of slots. In a preferred embodiment of the invention, the searching step uses a greedy resource allocation strategy to search a channel-chunk matrix comprising a list of contiguous chunks of available time slots in each frequency of the shared frequency-time sliced wireless medium. The greedy resource allocation strategy comprises the following successive allocation steps: searching for a single contiguous set of available time slots in a single frequency, where the size of the set of available slots is equal to the requested size [60]; searching for a single contiguous set of available time slots in a single frequency, where the size of the set of available slots is greater than the requested size [64]; searching for separate chunks of available time slots in a single frequency [66]; and searching for separate chunks of available time slots in multiple frequencies [68]. Each allocation step comprises checking whether the allocation violates a frequency switching constraint.

The present invention provides an antenna for multiple bands employing a single antenna element 10, capable of operating in multiple frequency bands, and ideal for size reduction purposes. One end A of an antenna element 10 is electrically connected to a feeding point 12 and intermediate points B and C and the other end thereof is electrically connected via switches SWb, SWc, and SWd to a ground conductor 14. The electrical lengths of the antenna element 10 from the terminal to the intermediate points B and C plus connection lines from these points via the switches SWb and SWc to the ground conductor 14 and the electrical length from the one end A to the other end D plus a connection line from the other end via the switch SWd to the ground conductor 14 are set to be capable of resonating different desired frequency bands. By closing one of the switches SWb, SWc, and SWd, one of the desired frequencies can be selected and the antenna can resonate with that frequency. Thus, the antenna employing the single antenna element 10 can operate in multiple frequency bands.

Satellite radioterminal communications systems, methods and components thereof, can use multiple frequency segments of at least one satellite frequency band, multiple air interfaces, multiple spectrum reuse cluster sizes and/or multiple geographic cell sizes. For example, a space-based component is configured to communicate with first radioterminals in first satellite cells over a first frequency segment of a satellite frequency band, such as a first frequency segment of a satellite L-band, and to communicate with second radioterminals in second satellite cells over a second frequency segment of the same or different satellite frequency band. The space-based component also may be configured to communicate with a first radioterminal over a first air interface and to communicate with the second radioterminals over a second air interface.

Wireless devices, and particularly mobile devices such as cellphones, PDAs, computers, navigation devices, etc., as well as other devices which transmit or receive data or other signals at multiple frequency bands utilize at least one antenna to transmit and receive and a plurality of different bands (e.g., GSM cellular communication band; Bluetooth short range communication band; ultrawideband (UWB) communications, etc.). These wireless devices can simultaneously transmit or receive at a plurality of different bands, or simultaneously transmit and receive at different bands. The wireless devices have the ability to use a single physical structure (e.g., an antenna) for transmission and reception of many different bands. The antenna can be either actively tuned or passively tuned using one or more elements.

The present application discloses, inter alia, a system for improving the aggregate throughput of a wireless local area network which includes: at least one access point that is equipped with at least one transceiver configured to simultaneously transmit and receive at multiple frequencies using multiple channels; and the access point being configured to acquire channel conditions of users and to pool sets of users on the channels based on the channel conditions.

An array antenna apparatus includes a first feeding element having a first feed point, a second feeding element having a second feed point, and a first parasitic element electrically connected to the respective first and second feeding elements. In a first frequency band, respective resonances in the feeding elements occur independent of each other, by eliminating electromagnetic mutual coupling between the feeding elements, and exciting the first feeding element through the first feed point as well as exciting the second feeding element through the second feed point. In a second frequency band lower than the first frequency band, a loop antenna having a certain electrical length is formed by the first and second feeding elements and the first parasitic element, and a resonance of the loop antenna substantially occurs by exciting the first feeding element through the first feed point.

The invention provides an antenna system for wireless communications and in particular to a multiple antenna system for operation in conjunction with a radio frequency (RF) front end for wireless communication. The antenna system comprises one or more antennas configurable for transmission and reception in a first set of configurations and configured for transmission in a second set of configurations. The antenna system further comprises two or more antennas configurable for MIMO-diversity reception for the second set of configurations. The antennas that are configured for MIMO-diversity reception may be tuneable, and may have similar characteristics to enhance MIMO reception. Mobile communications terminals utilizing the antenna system, and radio-frequency (RF) front ends for operation in conjunction with the antenna system are also provided. The antenna system may support communications in multiple frequency bands and/or multiple communication standards of operation.