[Show abstract][Hide abstract] ABSTRACT: The interaction between passive Low Frequency (LF) and Ultra-High Frequency (UHF) tags in a dual frequency Radio Frequency Identification (RFID) tag is studied. This interaction is observed by building a dual frequency system from commercially available readers and experimentally determining the read range with the mutual coupling effects between the antennas. It is shown that by proper placement of the tags the individual performance of each tag can be preserved in the presence of mutual coupling.
Antennas and Propagation Society International Symposium, 2009. APSURSI '09. IEEE; 07/2009
[Show abstract][Hide abstract] ABSTRACT: A new planar meander-line antenna for passive UHF radio frequency identification (RFID) tags is presented. Specifically, a meander-line antenna is loaded periodically with coplanar waveguide (CPW) LC elements traditionally found in right/left-handed waveguide structures. It is shown that by using the antenna presented in this letter in a prototype passive UHF RFID tag, effective read ranges up to 4.87 m can be achieved. Many different dielectric substrates and CPW-LC load dimensions are investigated to illustrate how the input impedance, gain, and overall dimensions of the antenna are affected by these structural differences. It is shown that the overall dimension of the meander-line antenna can be reduced by slightly more than 18% with the introduction of the CPW-LC elements to the design. Several of the simulation results are validated by comparison with measurements.
[Show abstract][Hide abstract] ABSTRACT: This paper developed three control schemes to coordinate maximum power extraction and voltage control for doubly fed induction generators wind turbines during wind fluctuation. Via PWM, the rotor-side converter can generate a controllable AC voltage with controllable magnitude and frequency. Based on PWM, control schemes: slip control, flux magnitude and angle (FMA) control and vector control are developed. Wind turbine aerodynamics are modeled in dynamic simulation and to obtain a lookup table for torque/power control. In slip control, the voltage is coordinated with torque via voltage/Hz type control. In FMA control, the inner feedback loops of rotor flux magnitude and angle are developed. Torque control loop is added outside the flux angle control loop while voltage control loop is added outside of the flux magnitude control loop. In vector control, the power control loop and voltage control loop are added as the outside control loops while the current control loops is designated as the inner control loops. The purpose of the voltage control is to keep a constant stator voltage, and the power/torque control is used to get maximum wind power under varying wind speeds. Dynamic performance and robustness of the three control schemes are analyzed via linear system analysis tools (Bode plots). Matlab-based time-domain simulations are performed to verify the analysis results and the proposed control schemes.
[Show abstract][Hide abstract] ABSTRACT: A printed Rampart line antenna with a dielectric superstrate for passive radio frequency identification (RFID) tags is presented. A design process is outlined to determine the number of elements used in the rampart line antenna to achieve the required gain for the desired read range. An inductive loop is then added to the port to match the antenna with the passive tag circuitry. It is shown that a passive tag with a printed Rampart line antenna and a dielectric superstrate can achieve comparable read ranges to commercially available passive RFID tags.
RFID, 2008 IEEE International Conference on; 05/2008
[Show abstract][Hide abstract] ABSTRACT: A novel metal oxide based electronic nose system was designed and developed to detect Salmonella contamination in packaged meat (beef). This system contained an array of metal oxide detectors and custom made electronics for acquiring olfactory signature of the volatile organic compounds in the headspace of the meat packages produced by detector arrays. The acquired signals were processed using three wavelet packet transforms (WPT) for simultaneous noise reduction and compression. The coefficients of wavelet packets were used as features for developing statistical classification models using bootstrapped linear and quadratic discriminant analysis techniques. The average total classification accuracies for classifying Salmonella contaminated meat samples were higher than 82% with highest average accuracy of about 88%.
Sensors Applications Symposium, 2008. SAS 2008. IEEE; 03/2008
[Show abstract][Hide abstract] ABSTRACT: Present adaptive control schemes are formulated to estimate constant parameters. In certain circumstances, however, time-varying parameters may need to be estimated. This paper presents a method for estimating parameters that vary si nusoidally based upon the passivity/hyperstability formulation.
International Journal of Adaptive Control and Signal Processing 01/1996; 10(1):85-92. · 1.22 Impact Factor