The Experts below are selected from a list of 27 Experts worldwide ranked by ideXlab platform
Kamran Entesari - One of the best experts on this subject based on the ideXlab platform.
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a metamaterial inspired miniaturized wide band microwave interferometry sensor for liquid chemical detection
International Microwave Symposium, 2016Co-Authors: Ali Pourghorban Saghati, Jaskirat Singh Batra, Jun Kameoka, Kamran EntesariAbstract:This paper presents a miniature wide-band interferometry sensor for dielectric spectroscopy and detection of liquid chemicals based on utilizing two composite right/left-handed (CRLH) transmission lines (TLs) in a zero-IF mixing configuration. The equivalent series capacitance of the CRLH TLs, constructed by using microstrip interdigital Capacitors, is loaded with microfluidic channels, and exposed to the material under test (MUT) to act as the Sensing element. Due to the nonlinear dispersion relation of the artificial TLs with respect to the Sensing Capacitor, higher sensitivity over a frequency band as wide as 4–8 GHz is achieved, compared to the previously-reported resonator- or Capacitor-based sensors. The final fabricated system prototype is 4 cm×8 cm. Moreover, a calibration method is presented based on measurement results, which shows an rms error less than ∼1.5% for liquid-chemical permittivity detection. To the best of author's knowledge, this is the first disclosure of wide-band and highly-sensitive microwave interferometry sensor suitable for portable lab-on-board applications.
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a 1 8 ghz miniaturized spectroscopy system for permittivity detection and mixture characterization of organic chemicals
IEEE Transactions on Microwave Theory and Techniques, 2012Co-Authors: Ahmed A Helmy, Kamran EntesariAbstract:In this paper, a miniaturized broadband dielectric spectroscopy system is presented for permittivity detection, chemical Sensing, and mixture characterization for 1-8-GHz frequency range. A Sensing Capacitor exposed to the material under test (MUT) is part of a true time-delay (TTD) cell excited by a microwave signal at the Sensing frequency of interest. The phase shift of the microwave signal at the output of the TTD cell compared to its input is a measure of the permittivity of MUTs. For wideband and accurate Sensing, TTD cells are cascaded in a reconfigurable fashion to increase the detected phase shift, especially at low frequencies. TTD cells are designed to detect permittivities within the range of 1-30 considering nonideal effects, such as electromagnetic coupling between adjacent TTD cells. Calibration using reference liquids is applied to the fabricated sensor and sensor characteristics are extracted. Permittivity detection of organic chemicals is performed in the range of 1-8 GHz with an error less than 2%. The measured permittivities in the 1-8-GHz range are used to estimate the sub-1-GHz permittivities of MUTs using extrapolation. The Sensing system is also used for mixture characterization to find the mixing ratios in binary mixtures with an accuracy of 1%.
Ahmed A Helmy - One of the best experts on this subject based on the ideXlab platform.
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a 1 8 ghz miniaturized spectroscopy system for permittivity detection and mixture characterization of organic chemicals
IEEE Transactions on Microwave Theory and Techniques, 2012Co-Authors: Ahmed A Helmy, Kamran EntesariAbstract:In this paper, a miniaturized broadband dielectric spectroscopy system is presented for permittivity detection, chemical Sensing, and mixture characterization for 1-8-GHz frequency range. A Sensing Capacitor exposed to the material under test (MUT) is part of a true time-delay (TTD) cell excited by a microwave signal at the Sensing frequency of interest. The phase shift of the microwave signal at the output of the TTD cell compared to its input is a measure of the permittivity of MUTs. For wideband and accurate Sensing, TTD cells are cascaded in a reconfigurable fashion to increase the detected phase shift, especially at low frequencies. TTD cells are designed to detect permittivities within the range of 1-30 considering nonideal effects, such as electromagnetic coupling between adjacent TTD cells. Calibration using reference liquids is applied to the fabricated sensor and sensor characteristics are extracted. Permittivity detection of organic chemicals is performed in the range of 1-8 GHz with an error less than 2%. The measured permittivities in the 1-8-GHz range are used to estimate the sub-1-GHz permittivities of MUTs using extrapolation. The Sensing system is also used for mixture characterization to find the mixing ratios in binary mixtures with an accuracy of 1%.
Yun Kwang-seok - One of the best experts on this subject based on the ideXlab platform.
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MEMS capacitive pressure sensor monolithically integrated with CMOS readout circuit by using post CMOS processes
BioMed Central Ltd., 2017Co-Authors: Jang Munseon, Yun Kwang-seokAbstract:Abstract In this paper, we presents a MEMS pressure sensor integrated with a readout circuit on a chip for an on-chip signal processing. The capacitive pressure sensor is formed on a CMOS chip by using a post-CMOS MEMS processes. The proposed device consists of a Sensing Capacitor that is square in shape, a reference Capacitor and a readout circuitry based on a switched-Capacitor scheme to detect capacitance change at various environmental pressures. The readout circuit was implemented by using a commercial 0.35\ua0\u3bcm CMOS process with 2 polysilicon and 4 metal layers. Then, the pressure sensor was formed by wet etching of metal 2 layer through via hole structures. Experimental results show that the MEMS pressure sensor has a sensitivity of 11\ua0mV/100\ua0kPa at the pressure range of 100\u2013400\ua0kPa
Wonchan Kim - One of the best experts on this subject based on the ideXlab platform.
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A 600-dpi capacitive fingerprint sensor chip and image-synthesis technique
IEEE Journal of Solid-State Circuits, 1999Co-Authors: Jeong Woo Lee, Dong-jin Min, Jiyoun Kim, Wonchan KimAbstract:This paper examines the possibility of a low-cost, high-resolution fingerprint sensor chip. The test chip is composed of 64×256 Sensing cells (chip size: 2.7×10.8 mm2). A new detection circuit of charge sharing is proposed, which eliminates the influences of internal parasitic capacitances. Thus, the reduced Sensing-Capacitor size enables a high resolution of 600 dpi, even using a conventional 0.6 μm CMOS process. The partial fingerprint images captured are synthesized into a full fingerprint image with an image-synthesis algorithm. The problems and possibilities of this image-synthesis technique are also analyzed and discussed
Moslehi Bajestan Masoud - One of the best experts on this subject based on the ideXlab platform.
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Novel RF CMOS Integrated Circuits and Systems for Broadband Dielectric Spectroscopy
2016Co-Authors: Moslehi Bajestan MasoudAbstract:Broadband dielectric spectroscopy has proven to be a valuable technique for characterization of chemicals and biomaterials. It has the great potential to become an indispensable and cost-effective tool in point-of-care medical applications due to its label-free and non-invasive operation. However, most of the existing dielectric spectroscopy instruments require bulky, heavy and expensive measurement set-up, restricting their use to only special applications in industry and laboratories. Therefore, integrated dielectric spectroscopy on silicon capable of direct detection of chemicals/biomaterials' complex permittivity can yield significant cost and size reduction, system integration, portability, enormous processing, and high throughput. A CMOS wideband dielectric spectroscopy system is proposed for chemical and biological material characterization. The complex permittivity detection is performed using a configurable harmonic-rejecting receiver capable of indirectly measuring the complex admittance of Sensing Capacitor exposed to the material-under-test (MUT) and subject to RF signal excitation with a frequency range of 0.62-10 GHz. The Sensing Capacitor is embedded in a voltage divider topology with a fixed Capacitor and the relative variations in the magnitude and phase of the voltages across the Capacitors are used to find the real and imaginary parts of the permittivity. The sensor achieves an rms permittivity error of less than 1% over the entire operation bandwidth. Using a sub-harmonic mixing scheme, the system can perform complex permittivity measurements from 0.62 to 10 GHz while requiring an input signal source with frequency range of only from 5 to 10 GHz. Thereby, the permittivity measurement system can be easily made self-sustained by implementing a 5-10 GHz frequency synthesizer on the same chip. One of the key building blocks in such a frequency synthesizer is the voltage-controlled oscillator (VCO) which has to cover an octave of frequency range. A novel low-phase-noise wide-tuning range VCO is presented using a triple-band LC resonator. The implemented VCO in 0.18μm CMOS technology achieves a continuous tuning range of 86.7% from 5.12 GHz to 12.95 GHz while drawing 5 to 10 mA current from 1-V supply. The measured phase noise at 1 MHz offset from carrier frequencies of 5.9, 9.12 and 12.25 GHz is -122.9, -117.1 and -110.5 dBc/Hz, respectively. Also, a dual-band quadrature voltage-controlled oscillator (QVCO) is presented using a transformer-based high-order LC-ring resonator which inherently provides quadrature signals without requiring noisy coupling transistors as in traditional approaches. The proposed resonator shows two possible oscillation frequencies which are exploited to realize a wide-tuning range QVCO employing a mode-switching transistor network. Due to the use of transformers, the oscillator has minimal area penalty compared to the conventional designs. The implemented prototype in a 65-nm CMOS process achieves a continuous tuning range of 77.8% from 2.75 GHz to 6.25 GHz while consuming 9.7 to 15.6 mA current from 0.6-V supply. The measured phase noise figure-of-merit (FoM) at 1 MHz offset ranges from 184 dB to 188.2 dB throughout the entire tuning range. The QVCO also exhibits good quadrature accuracy with 1.5º maximum phase error and occupies a relatively small silicon area of 0.35 mm^2
