Channel arrangement in multi-reader RFID system Changzhan Gu; Shan Qiao; Wangzhao Cui ...
IET Conference on Wireless, Mobile and Sensor Networks 2007 (CCWMSN07),
2007
Conference Proceeding
China has recently promulgated its regulation on UHF RFID application, including the technology of frequency hopping. RFID readers use different channels to minimize collision. However, readers that ...work in the same or adjacent channels will cause bad signal to noise ratio (SNR) at the RF front-end of readers, which may reduce the reliability and efficiency of the RFID system. This paper concentrates on the study on the multi-reader situation, and attempts to propose an optimization algorithm to optimize the channel arrangement and to improve the system efficiency. The simulation results presented in this paper are obtained by using MATLAB.
Ultra high frequency radio frequency identification (UHF RFID) system is becoming more wide spread due to its advantages, such as fast read-write speed, large memory, long recognition distance and ...the capacity of simultaneously reading/writing multi-tags. In this paper, we introduce the characteristics, structure, principle and read/write method of a UHF RFID reader, and present the solution of its interrogator and flow of DSP software program. Received backscatter modulation waves are directly demodulated to basedband signals using zero IF technology. The reader is designed as a quadrature (I/Q) one, which can avoid null points of received signals and enhance the demodulation sensitivity.
PXI-based non-contact vital sign detection system Banerjee, Sharmi; Gu, Changzhan; Li, Changzhi
2014 IEEE Topical Conference on Biomedical Wireless Technologies, Networks, and Sensing Systems (BioWireleSS),
2014-Jan.
Conference Proceeding
This paper presents a novel noncontact vital sign detection (VSD) system, which integrates an entire radar transceiver along with advanced signal processing algorithms in one compact PXI (Peripheral ...Component Interconnect eXtensions for Instrumentation) system. Realtime signal processing has been implemented using automatic DC calibration based on compressed sensing algorithm and 'differentiate and cross-multiply' (DACM) demodulation algorithm. Experimental results show that the proposed compact instrument based radar is able to measure respiration motions with simple hardware configuration. This facilitates many proof-of-concept studies for noncontact vital sign detection.
Doppler radar has the capability to remotely monitor human respiration. However, in real applications random body movements during measurement will cause drift of "DC" level in the experiment ...results. Also, the dc level will shift slowly with the temperature change of the radar circuit. Those DC drifts will cause inaccurate measurement results. To solve the dc drift issue during the experiments, an automatic DC-correction algorithm is developed. Experiment results show that this algorithm eliminates undesirable DC drifts and offset while recovering useful information of the original respiration signal. It is able to provide reliable respiration measurement even if there are large body movements that otherwise overwhelm the desired signal.
In this paper, a simple and single-layer probe-fed ul-trawideband (UWB) microstrip patch antenna with an annular gap at the X band and Ku band is proposed. The annular gap is used to compensate for ...the inductance caused by the probe-fed by introducing a capacitor value. The influence of antenna parame-ters on performance is analyzed thoroughly. Prototypes are de-signed, simulated, fabricated, and measured to verify the proposed UWB patch antenna. The simulated and measured results demon-strate that the proposed UWB patch antenna possesses the merit of wide operating bandwidth (up to 52%), and the maximum and minimum gains are 7.44 dBi at 9.19 GHz and 3.5 dBi at 13.06 GHz, respectively, which provides a foundation for the applications in broadband scenarios.
The application of radar sensors to monitor vital signs is currently receiving much attention. Several radar architectures have been proposed in the technical literature for this task, although with ...some limitations. Here, a linear-frequency-modulated continuous-wave (LFMCW) approach is analyzed. By extracting the phase of particular range bins, precise tracking of vital signs (e.g., breathing) could be accomplished, outperforming other approaches. A prototype has been built and some experimental data coming from a sinusoidally-moving metal plate are presented. Also, preliminary results for breathing signals are shown and discussed.
Since the debut of medical radar sensors nearly four decades ago, there have been many technical advancements that helped this technology mature. Progresses have been seen from system architectures ...to signal processing algorithms. Many research efforts have been dedicated to utilize the radar sensors for different biomedical applications such as noncontact vital sign detection, human fall detection, through-wall detection, and medical imaging. A special application is radar respiration measurement in motion-adaptive cancer radiotherapy. The radar measures the respiration pattern that is used to infer the tumor location in real time. To realize accurate respiration pattern measurement, the signal distortion problem in a conventional CW radar sensor was extensively analyzed, and the solution led to a dc-coupled radar that is distortion-free. Successful preliminary clinical tests have been carried out using the radar sensor in a radiotherapy environment, demonstrating its feasibility. The same dc-coupled physiological radar sensor solution also shows the potential of monitoring the physical states and speech of the subject person.
Radars are among the best exponents of radio-frequency (RF)/microwave devices for remote sensing 1, 2. Long-range radars have demonstrated outstanding potential not only for defense/security ...environments, such as the detection, location, and tracking of targets, but also on a plurality of civilian scenarios, such as meteorological/weather measurement tasks, imaging of the Earth's surface through synthetic aperture radar (SAR) techniques, monitoring of animal migrations, and many others 3-7.
Since the debut of iOS and Android smartphones 10 years ago, the world has seen a mobile era wherein our phones have become a mobile computing platform deeply integrated into our lives 1-4. Due to ...the advancement of computing, it is believed that the world is shifting to a new era where artificial intelligence (AI) is unlocking capabilities that were previously unthinkable 5-13. Because computing is becoming more universally available, interaction with computing devices needs to be much more natural, intuitive, and, above all, intelligent 14.
