Showing papers on "Radio frequency published in 2003"

Pentacene-based radio-frequency identification circuitry

Abstract: Pentacene-based thin-film integrated circuits patterned only with polymeric shadow masks and powered by near-field coupling at radio frequencies of 125 kHz and above 6 MHz have been demonstrated. Sufficient amplitude modulation of the rf field was obtained to externally detect a clock signal generated by the integrated circuit. The circuits operate without the use of a diode rectification stage. This demonstration provides the basis for more sophisticated low-cost rf transponder circuitry using organic semiconductors.

System and method for management of a shared frequency band

Abstract: A system, method, software and related functions are provided for managing activity in a radio frequency band that is shared, both in frequency and time, by signals of multiple types. An example of such a frequency band is an unlicensed frequency band. Radio frequency energy in the frequency band is captured at one or more devices and/or locations in a region where activity in the frequency band is happening. Signals occurring in the frequency band are detected by sampling part or the entire frequency band for time intervals. Signal pulse energy in the band is detected and is used to classify signals according to signal type. Using knowledge of the types of signals occurring in the frequency band and other spectrum activity related statistics (referred to as spectrum intelligence), actions can be taken in a device or network of devices to avoid interfering with other signals, and in general to optimize simultaneous use of the frequency band with the other signals. The spectrum intelligence may be used to suggest actions to a device user or network administrator, or to automatically invoke actions in a device or network of devices to maintain desirable performance.

Multiple-input multiple-output radio transceiver

Abstract: A MIMO radio transceiver to support processing of multiple signals for simultaneous transmission via corresponding ones of a plurality of antennas and to support receive processing of multiple signals detected by corresponding ones of the plurality of antennas. The radio transceiver provides, on a single semiconductor integrated circuit, a receiver circuit or path for each of a plurality of antennas and a transmit circuit or path for each of the plurality of antennas. Each receiver circuit downconverts the RF signal detected by its associated antenna to a baseband signal. Similarly, each transmit path upconverts a baseband signal to be transmitted by an assigned antenna.

System and method for management of a shared frequency band using client--specific management techniques

Abstract: A system and method are provided for managing communication with a plurality of wireless client devices operating in a radio frequency band shared by other types of devices, comprising a step of controlling at least one parameter associated with radio communication with each of the plurality of wireless devices based on the radio frequency environment associated with each corresponding one of the plurality of wireless client devices. Spectrum profile information describing the radio frequency environment (activity in the frequency band) at a wireless client device is sent to the wireless base station device (where the parameter controls are made) from either a wireless client device or another radio device in the proximity of one or more wireless client devices that is capable of generating the spectrum profile information. The spectrum profile information may include information identifying signals that are occurring in the frequency band in the proximity of a wireless client device. Examples of parameters that may be controlled at the wireless base station device include packet fragmentation threshold (the length of a data packet), transmission data rate and transmission scheduling (synchronizing a transmission to quiescent intervals of one or more periodic interfering signals).

Radio frequency heating of foods: principles, applications and related properties--a review.

Abstract: Radio frequency (RF) heating is a promising technology for food applications because of the associated rapid and uniform heat distribution, large penetration depth and lower energy consumption Radio frequency heating has been successfully applied for drying, baking and thawing of frozen meat and in meat processing However, its use in continuous pasteurization and sterilization of foods is rather limited During RF heating, heat is generated within the product due to molecular friction resulting from oscillating molecules and ions caused by the applied alternating electric field RF heating is influenced principally by the dielectric properties of the product when other conditions are kept constant This review deals with the current status of RF heating applications in food processing, as well as product and system specific factors that influence the RF heating It is evident that frequency level, temperature and properties of food, such as viscosity, water content and chemical composition affect the dielectric properties and thus the RF heating of foods Therefore, these parameters should be taken into account when designing a radio frequency heating system for foods

Implementing Radio Frequency Identification in the Construction Process

Abstract: This paper provides construction industry owners and contractors with information about enhancing their operations using radio frequency identification (RFID) technology. Radio frequency identifica...

Handpiece with electrode and non-volatile memory

Abstract: An apparatus for cooling a skin surface includes an RF device that has an RF electrode with dielectric and conductive portions. The RF device is configured to be coupled to an RF energy source. A cooling member is coupled to the RF device. A memory is coupled to the RF device. The memory is configured to store information to facilitate operation of at least one of the RF electrode, the cooling member, and the RF energy source.

RF point of sale and delivery method and system using communication with remote computer and having features to read a large number of RF tags

Abstract: A method and system for providing point-of-sale and point-of-delivery and/or distribution of products in a restricted access unit near the customer. The method and system utilize products equipped with radio frequency tags and reduce the effects of energy sharing, shadowing, and nulls. In one embodiment, a plurality of RF tagged products are placed within a refrigerator, cabinet, or other micro-warehouse that has a door or opening that can detect access to the micro-warehouse. In one embodiment, one or more antennas are positioned within the door. Each antenna may have a transmission line of sight and be configured to emit a signal at predefined frequencies. Each antenna generates an electromagnetic field within the micro-warehouse. In one embodiment, the products are positioned in one or more bins, compartments, or similar devices located within the micro-warehouse such that at least two of the plurality of products are spaced a distance from each other to reduce energy sharing. The electromagnetic field is moved or altered within the micro-warehouse through the use of reflectors, devices that move the antennas, or other mechanisms.

MEMS for wireless communications: 'from RF-MEMS components to RF-MEMS-SiP'

Abstract: Wireless communication has led to an explosive growth of emerging consumer and military applications of radio frequency (RF), microwave and millimeter wave circuits and systems. Future personal (hand-held) and ground communications systems as well as communications satellites necessitate the use of highly integrated RF front-ends, featuring small size, low weight, high performance and low cost. Continuing chip scaling has contributed to the extent that off-chip, bulky passive RF components, such as high-Q inductors, ceramic and SAW filters, varactor diodes and discrete PIN diode switches, have become limiting. Micro-machining or MEMS technology is now rapidly emerging as an enabling technology to yield a new generation of high-performance RF-MEMS passives to replace these off-chip passives in wireless communication (sub)systems. This paper reviews the progress in RF-MEMS from a device and integration perspective. The worldwide state-of-the-art of RF-MEMS devices including switches, variable capacitors, resonators and filters are described. Next, it is stipulated how integration of RF-MEMS passives with other passives (as inductors, LC filters, SAW devices, couplers and power dividers) and, active circuitry (ASICs, RFICs) can lead to the so-called RF-MEMS system-in-a-package (RF-MEMS-SiP) modules. The evolution of the RF-MEMS-SiP technology is illustrated using IMEC's microwave multi-layer thin-film MCM-D technology which today already serves as a technology platform for RF-SiP.

A novel power plane with integrated simultaneous switching noise mitigation capability using high impedance surface

Abstract: A novel technique for suppressing power plane resonance at microwave and radio frequencies is presented. The new concept consists of replacing one of the plates of a parallel power plane pair with a high impedance surface or electromagnetic band gap structure. The combination of this technique with a wall of RC pairs extends the lower edge of the effective bandwidth to dc, and allows resonant mode suppression up to the upper edge of the band-gap. The frequency range for noise mitigation is controlled by the geometry of the HIGP structure.

Radio Frequency Integrated Circuit Design

Abstract: Radio frequency integrated circuits (RFICs) are the building blocks that enable every device from cable television sets to mobile telephones to transmit and receive signals and data. This newly revised and expanded edition of the 2003 Artech House classic, "Radio Frequency Integrated Circuit Design", serves as an up-to-date, practical reference for complete RFIC know-how. The second edition includes numerous updates, including greater coverage of CMOS PA design, RFIC design with on-chip components, and more worked examples with simulation results. By emphasizing working designs, this book practically transports readers into the authors' own RFIC lab so they can fully understand how these designs function. This title is suitable for radio frequency integrated circuit (RFIC) design engineers; radio systems architects; researchers and developers of RFIC technology; and, graduate level electrical engineering students.

Optical and radio behaviour of the BL Lacertae object 0716+714 ⋆

Abstract: Eight optical and four radio observatories have been intensively monitoring the BL Lac object 0716+714 in the last years: 4854 data points have been collected in the UBVRI bands since 1994, while radio light curves extendback to 1978. Many of these data, which all together constitute the widest optical and radio database available on this object, are presented here for the first time. Four major optical outbursts were observed at the beginning of 1995, in late 1997, at the end of 2000, and in fall 2001. In particular, an exceptional brightening of 2.3 mag in 9 days was detected in the R band just before the BeppoSAX pointing of October 30, 2000. A big radio outburst lasted from early 1998 to the end of 1999. The long-term trend shown by the optical light curves seems to vary with a characteristic time scale of about 3.3 years, while a longer period of 5.5-6 years seems to characterize the radio long-term variations. In general, optical colour indices are only weakly correlated with brightness; a clear spectral steepening trend was observed during at least one long-lasting dimming phase. Moreover, the optical spectrum became steeper after JD ∼ 2451 000, the change occurring in the decaying phase of the late-1997 outburst. The radio flux behaviour at different frequencies is similar, but the flux variation amplitude decreases with increasing wavelength. The radio spectral index varies with brightness (harder when brighter), but the radio fluxes seem to be the sum of two different-spectrum contributions: a steady base level and a harder-spectrum variable component. Once the base level is removed, the radio variations appear as essentially achromatic, similarly to the optical behaviour. Flux variations at the higher radio frequencies lead the lower-frequency ones with week-month time scales. The behaviour of the optical and radio light curves is quite different, the broad radio outbursts not corresponding in time to the faster optical ones and the cross-correlation analysis indicating only weak correlation with long time lags. However, minor radio flux enhancements simultaneous with the major optical flares can be recognized, which may imply that the mechanism producing the strong flux increases in the optical band also marginally affects the radio one. On the contrary, the process responsible for the big radio outbursts does not seem to affect the optical emission.

Development and performance analysis of an intra-body communication device

Abstract: Personal area networks would benefit from a wireless communication system in which a variety of information could be exchanged through wearable electronic devices and sensors. Intra-body communication using the human body as the transmission medium enables wireless communication without transmitting radio waves through the air. A human arm phantom is designed and used to reduce uncertainty in experiments with the human body. The phantom exhibits transmission characteristics similar to those of the human body at frequencies between 1 MHz and 10 MHz. A 10.7 MHz frequency modulation (FM) intra-body transmitter and receiver are developed which allow transmission of analog sine waves even in the presence of external noise. Digital data transmission at 9600 bps was also achieved using newly fabricated 10.7 MHz frequency shift keying (FSK) transmitter and receiver devices. The carrier frequency of 10.7 MHz, which is the intermediate frequency in FM radio receivers, means that a wide selection of commercial radio frequency (RF) devices is available.

Detection of transient in radio frequency fingerprinting using signal phase

Abstract: Radio Frequency Fingerprinting (RFF) is a technique, which has been used to identify wireless devices It essentially involves the detection of the transient signal and the extraction of the fingerprint The detection phase, in our opinion, is the most challenging yet crucial part of the RFF process Current approaches, namely Threshold and Bayesian Step Change Detector, which use amplitude characteristics of signals for transient detection, perform poorly with certain types of signals This paper presents a new algorithm that exploits the phase characteristics for detection purposes Validation using Bluetooth signals has resulted in a success rate of approximately 85-90 percent We anticipate that the higher detection rate will result in a higher classification rate and thus support various device authetication schemes in the wireless domain

The Design of CMOS Radio-Frequency Integrated Circuits: RF CIRCUITS THROUGH THE AGES

Abstract: This expanded and thoroughly revised edition of Thomas H. Lee's acclaimed guide to the design of gigahertz RF integrated circuits features a completely new chapter on the principles of wireless systems. The chapters on low-noise amplifiers, oscillators and phase noise have been significantly expanded as well. The chapter on architectures now contains several examples of complete chip designs that bring together all the various theoretical and practical elements involved in producing a prototype chip. First Edition Hb (1998): 0-521-63061-4 First Edition Pb (1998); 0-521-63922-0

Apparatus for a wireless animal trap detection system

Abstract: Systems are described for a wireless animal trap detection system. An apparatus includes an animal trap, a wireless radio frequency (RF) transmitter coupled to the animal trap wherein the wireless RF transmitter transmits a series of signals at substantially random intervals upon activation of the animal trap, and a receiver configured to receive the series of signals from the wireless RF transmitter.

Delivery of high-stability optical and microwave frequency standards over an optical fiber network

Abstract: Optical and radio frequency standards located in JILA and National Institute of Standards and Technology (NIST) laboratories have been connected through a 3.45-km optical fiber link. An optical frequency standard based on an iodine-stabilized Nd:YAG laser at 1064 nm (with an instability of ∼4×10-14 at 1 s) has been transferred from JILA to NIST and simultaneously measured in both laboratories. In parallel, a hydrogen maser-based radio frequency standard (with an instability of ∼2.4×10-13 at 1 s) is transferred from NIST to JILA. Comparison between these frequency standards is made possible by the use of femtosecond frequency combs in both laboratories. The degradation of the optical and rf standards that are due to the instability in the transmission channel has been measured. Active noise cancellation is demonstrated to improve the transfer stability of the fiber link.

Ad-Hoc Control Protocol Governing Use of an Unlicensed or Shared Radio Frequency Band

Abstract: Systems and methods to enable different types of radio communication devices to communicate using a common language in order to enable the devices to regulate their use of the spectrum. Each device participating in the ad hoc control channel (ACC) protocol transmits information using a common signal format that each of the other participant devices is capable of recognizing, in order to share information about how it uses the radio frequency band. Each device receives the information transmitted by other participant devices and based on that information, controls one or more of its operational parameters that impact usage of the radio frequency band. The ACC protocol enables devices of the same or different type to harmonize (instead of alienate) themselves with each other by allowing them to communicate about their usage of the radio frequency band using a common signaling framework. Improvement can be achieved in spectrum efficiency and ultimately provide a more reliable and enjoyable experience for the end user of a device that operates in that radio frequency band.

Conditioning of coupled electromagnetic signals on a lead

Abstract: A method and an apparatus for reducing coupled electrical energy resulting from an electromagnetic field. Embodiments of the present invention provide for an elongate body having a proximal end portion, a middle portion, and a distal end portion and at least one coil wound about at least one of the proximal end portion, the middle portion, and the distal end portion, the coil to provide for filtering of radio frequency (RF) signal-coupled electrical energy.

Direct-conversion transceiver enabling digital calibration

Abstract: A transceiver for transmitting and receiving signals includes a transmitter operative to up-convert baseband signals from a baseband frequency into RF signals at a radio frequency (RF) frequency and output the RF signals, a receiver operative to receive RF signals and down-convert the RF signals into baseband signals having the baseband frequency, and a plurality of calibration paths coupling the transmitter to the receiver. Any of the calibration paths can be selected to be active when calibrating components of the transceiver. Tunable components can use calibration information to optimize transceiver performance.

A 1.9GHz RF Transmit Beacon using Environmentally Scavenged Energy

Abstract: The design and implementation of a 1.9GHz radio frequency transmit beacon is presented. The beacon is completely selfcontained, and all necessary energy is scavenged through solar and vibrational energy sources. Custom RF integrated circuitry and energy scavenging devices are used to create a highly integrated and efficient beacon. The 1.9GHz direct modulated transmitter uses a micromachined resonator and requires no other external components, inductors, or crystals. The beacon achieves duty cycles up to 100% for typical ambient solar conditions and 2.6% for typical ambient vibrational conditions.

Radio frequency identification parts verification system and method for using same

Abstract: A system and method for collecting data relating to the parts of a vehicle and using such data to determine if the vehicle can be operated. The system entails the deployment of a plurality of radio frequency identification tags on or within various parts of the vehicle that are capable of issuing radio frequency signals containing data related to each corresponding part. A radio frequency transceiver capable of interfacing with and receiving data stored within each tag operates in conjunction with a central processor unit capable of analyzing the data from each tag and determining whether the vehicle needs parts to be replaced or can be operated with its existing set of parts.

Integrated radar and communications based on chirped spread-spectrum techniques

Abstract: Linear frequency modulated (LFM) signals and the associated pulse compression techniques are attractive in applications where highly secure and robust communication is needed. This paper investigates the novel integration of radar and communications utilizing LFM waveforms. The simulations suggest that the performance of the communications-receiver deviates at most 2 dB from the theoretical probability of bit error for /spl pi//4-differential phase shift keying. The simulated radar receiver-operating characteristics for false-alarm probabilities between 10/sup -2/ and 10/sup -4/ also compares very well with the theoretical limits for a coherent system.

Self-selection of radio frequency channels to reduce co-channel and adjacent channel interference in a wireless distributed network

Abstract: A wireless network node and a network provide for automatic self-deployment of the radio frequency channels without the need for preplanning. Each wireless network node adapts to the inclusion of a new node and to changing local conditions without requiring manual configuration at deployment or re-deployment. When a node is added to the network, it scans and finds its neighbors, and enters a frequency self-selection phase of its initialization process. The method for frequency self-selection involves transmitting and receiving a sequence of messages to/from neighbors and performing related processing within the controller unit of the node. Three sets of parameters are used in the frequency self-selection algorithm. The three parameter sets include a routing cost function, the frequencies in use by neighbors (and those that may be blocked), and the antenna beams used for the respective frequencies.

Miniature radio-acoustic sounding system for low altitude wind and precipitation measurements

Abstract: The present invention is directed to a radio-acoustic sounding system for providing wind measurements at altitudes of 100 meters or less. Wind measurements are obtained by transmitting a pulse of audio frequency energy through one or more volumes corresponding to the coverage area of one or more radio frequency transceivers. The frequency of the audio pulse is selected to have a wavelength that is one-half the wavelength of the electromagnetic energy transmitted by the antenna or antennas. By monitoring a return radio frequency signal at selected times following the transmission of the audio pulse, wind data is obtained at selected altitudes. Wind speed and direction can be obtained by observing the Doppler frequency shift of return radio frequency signals, or by observing the amplitude of the return radio frequency signals. In accordance with an embodiment of the present invention, precipitation measurements may be made by transmitting a radio frequency signal at the same radio frequency as is used in connection with wind measurements, and observing return radio frequency signals.

System and method for controlling an implantable medical device subject to magnetic field or radio frequency exposure

Abstract: A system for controlling an implantable medical device (e.g., a drug delivery device) susceptible to malfunctioning during exposure to a magnetic field and/or Radio Frequency field (e.g., during a magnetic resonance imaging procedure) and a method for operating the same. Exposure of the implantable device to the magnetic field and/or the Radio Frequency field is detected using the sensing device. When the detected magnetic field and/or Radio Frequency field exceeds a corresponding predetermined threshold level, an input signal is generated at the microcontroller. In response to the generated input signal, the microcontroller automatically triggers (i) a safety mode enabling a predetermined safety mode operation that alters some operation, without ceasing all operation, of the implantable medical device and/or (ii) after expiration of a predetermined safety mode time interval when the at least one field being detected falls below its corresponding predetermined threshold level or a predetermined period of time elapses, a self testing mode enabling a predetermined self testing operation to verify proper operation of the implantable medical device. Preferably, both the safety and self testing modes are automatically triggered.

Determination of wheel sensor position using radio frequency detectors in an automotive remote tire monitor system

Abstract: In a remote tire monitor system, radio frequency (RF) signals including tire data are transmitted from a plurality of tire monitors at wheels of a vehicle. At an RF receiver, the signals are received and tire data is detected. The RF signals are detected at a receiving RF detector associated with the transmitting tire monitor. The receiving RF detector produces a transmission indication in response to the received RF signals. A control unit is coupled to the RF receiver and the RF detector. The control unit receives the tire data and the transmission indication and associates a position of the transmitting tire monitor with the tire data in response to transmission indication. This permits automatic update of the position of tire monitors on the vehicle.

The synthesis of metamaterial ferrites for RF applications using electromagnetic bandgap structures

Abstract: It has been well known for many years that the desirable properties of conventional ferrite materials are seriously degraded for frequencies above 1 GHz The paper demonstrates that electromagnetic bandgap (EBG) structures may be interpreted as an equivalent PEC-backed slab of magnetic material with a frequency dependent permeability A design methodology is presented for realizing a metaferrite material using a GA optimization procedure A standard HZ-FSS (high-impedance frequency selective surface) structure is shown to be equivalent to a thin PEC-backed slab of magnetic material with a frequency dependent permeability By optimizing the surface impedance of the HZ-FSS, it is possible to synthesize a metaferrite with nearly any desired real and imaginary values of permeability Finally, this design procedure allows for a low-loss negative permeability metaferrite to be realized, with potential application to the design of left-handed or double negative media

Radio frequency proximity detection and identification system and method

Abstract: Disclosed herein is a critical band encoding technology (CBET) system having at least one portable people meter (PPM) and a home base station and/or household hub, the CBET system containing a radio frequency (RF) proximity detection and identification system, comprising at least one RF transmitter for receiving a control signal, modulating an RF signal to a present modulation frequency upon receipt of the control signal, and wireless transmitting the modulated signal; and an RF receiver for receiving the wirelessly transmitted modulated signal, determining the modulation frequency, and transmitting the modulation frequency to a remote location, wherein the transmission power of the RF transmitter is preset to transmit the modulated data within a predetermined range.

Towards a propagation model for wireless biomedical applications

Abstract: Propagation model plays a very important role in designing wireless communication systems. Current advances in semiconductor technology has made it possible to implant a network of bio-sensors inside the human body for health monitoring purposes [C. Furse, H.K. Lai, C. Estes, A. Mahadik, A. Duncan, 1999], [C. Furse, R. Mohan, A. Jakayar, S. Karidehal, B. McCleod, S. Going, 2001], [L. Schwiebert, S.K.S. Gupta, P.S.G. Auner, G. Abrams, R. Lezzi, P. McAlister, 2002]. For wireless communication inside the human body, the tissue medium acts as a channel through which the information is sent as electromagnetic (EM) radio frequency (RF) waves. A propagation model is necessary to determine the losses involved in the form of absorption of EM wave power by the tissue. Absorption of EM waves by the tissue body, which consists of mostly saline water, accounts for a major portion of the propagation loss. In this paper we present a propagation loss model (PMBA) for homogeneous tissue bodies. We have verified the model for the frequency range of our interest (900 MHz to 3 GHz) using a 3D EM simulation software, HFSS/spl trade/, and experimental measurements using saturated salt water.