Sun, 27 Jul 2008 07:41:14 BST CiteULike: dcastro's Yu http://www.citeulike.org/user/dcastro/author/Yu CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/dcastro/article/2941950 <i>Journal of Zhejiang University - Science A, Vol. 6, No. 6. (13 June 2005), pp. 483-486.</i><br /><br />Abstract  A tunable dual-broad-band branch-line coupler (BLC) utilizing composite right/left-handed (CRLH) transmission lines is presented. Two λ/4 segments consisting of CRLH transmission lines are added to each port to broaden the dual bands of the branch-line coupler. Numerical simulation and optimal design of the novel coupler are presented. The dual bands of the novel coupler are tunable and broad. The 1-dB bandwidth of each passband is more than, 16% of the central frequency. A tunable dual-broad-band branch-line coupler utilizing composite right/left-handed transmission lines Zhang Yu Hu Li He Sai-Ling doi:10.1007/BF02841752 Journal of Zhejiang University - Science A, Vol. 6, No. 6. (13 June 2005), pp. 483-486. 2008-06-29T18:25:45-00:00 2005 Journal of Zhejiang University - Science A 6 6 483 486 broadband coupler crlh dual-band tl http://www.citeulike.org/user/dcastro/article/2802347 <i>Ultra Wideband Systems, 2004. Joint with Conference on Ultrawideband Systems and Technologies. Joint UWBST & IWUWBS. 2004 International Workshop on (2004), pp. 400-404.</i><br /><br />The paper reports on the development of a low-cost device for low data rate communications with tracking and positioning capabilities. We investigate the performance of two different position estimation methods based on the estimate of the time-of-arrival (TOA) of the UWB signal at a set of receivers/sensors. The performance evaluation is performed in terms of the root mean-squared (RMS) error of the position coordinates estimation and the failure rate. We first study the direct-calculation method which gives exact solutions of a set of simultaneous equations. We then study one of the classical nonlinear optimization techniques, the Davidon-Fletcher-Powell (DFP) quasi-Newton algorithm. Both the direct-calculation method and the nonlinear optimization algorithms do not require any knowledge of the TOA estimation error variance or distribution. This advantage would be attractive for practical applications. Performance of UWB position estimation based on time-of-arrival measurements Kegen Yu I Oppermann doi:10.1109/UWBST.2004.1321004 Ultra Wideband Systems, 2004. Joint with Conference on Ultrawideband Systems and Technologies. Joint UWBST & IWUWBS. 2004 International Workshop on (2004), pp. 400-404. 2008-05-15T18:37:42-00:00 2004 Ultra Wideband Systems, 2004. Joint with Conference on Ultrawideband Systems and Technologies. Joint UWBST & IWUWBS. 2004 International Workshop on 400 404 estimation measurement position time uwb http://www.citeulike.org/user/dcastro/article/2776272 <i>Electron Devices Meeting, 1997. IEDM '97. Technical Digest., International (1997), pp. 301-304.</i><br /><br />The rapid growth of wireless systems at radio frequencies (RF) is driving the need for improved analog circuit and device analysis at gigaHertz frequencies. This includes: low noise front ends, linear amplifiers, mixers, and power amplifiers. Moreover, the parasitic effects of capacitance and inductance, both on- and off-chip, require careful extraction and characterization in support of predictive modeling. While time-domain techniques work well for digital systems, often the spectral and dynamic range requirements for communications systems necessitate accurate analysis of harmonic content with frequency differences of a thousandfold or more. This paper demonstrates the applicability and unique strengths of device-level harmonic balance (HB) in the simulation and physical modeling of RF circuits Device simulation for RF applications RW Dutton B Troyanovsky Z Yu T Arnborg F Rotella G Ma J Sato-Iwanaga doi:10.1109/IEDM.1997.650386 Electron Devices Meeting, 1997. IEDM '97. Technical Digest., International (1997), pp. 301-304. 2008-05-09T16:40:13-00:00 1997 Electron Devices Meeting, 1997. IEDM '97. Technical Digest., International 301 304 rf simulation http://www.citeulike.org/user/dcastro/article/2776271 <i>Microwave Theory and Techniques, IEEE Transactions on, Vol. 48, No. 6. (2000), pp. 991-999.</i><br /><br />This paper describes how device simulation may be used for the modeling, analysis, and design of radio-frequency (RF) laterally diffused metal-oxide-semiconductor (LDMOS) transistors. Improvements to device analysis needed to meet the requirements of RF devices are discussed. Key modeling regions of the LDMOS device are explored and important physical effects are characterized. The LDMOS model is compared to dc and small-signal ac measurements for calibration purposes. Using the calibrated model, large-signal accuracy is verified using harmonic distortion simulation, and intermodulation analysis. Predictive analysis and a study of the structure's parasitic components are also presented. Load-pull simulation is used to analyze matching network effects to determine the best choices for device impedance matching Modeling, analysis, and design of RF LDMOS devices using harmonic-balance device simulation FM Rotella G Ma Z Yu RW Dutton doi:10.1109/22.904736 Microwave Theory and Techniques, IEEE Transactions on, Vol. 48, No. 6. (2000), pp. 991-999. 2008-05-09T16:40:12-00:00 2000 Microwave Theory and Techniques, IEEE Transactions on 48 6 991 999 analysis design model rf simulation http://www.citeulike.org/user/dcastro/article/2762214 <i>Lasers and Electro-Optics Society, 2002. LEOS 2002. The 15th Annual Meeting of the IEEE, Vol. 2 (2002), pp. 516-517 vol.2.</i><br /><br />The 3D FDTD method is used to obtain loss versus hole depth in a 2D photonic crystal waveguide by simulating two different length guides. The transmission results are validated against published measured data. Good agreement between measured and simulated data is obtained for a mini-stop band of the PC WG. Intrinsic loss has been extracted from different length guides and an estimate of the lower bound of waveguide loss has been made. Analysis of losses in 2D photonic crystal waveguides using the 3D finite difference time domain (FDTD) method MJ Cryan IJ Craddock S Yu CJ Railton J Rorison Lasers and Electro-Optics Society, 2002. LEOS 2002. The 15th Annual Meeting of the IEEE, Vol. 2 (2002), pp. 516-517 vol.2. 2008-05-06T18:28:39-00:00 2002 Lasers and Electro-Optics Society, 2002. LEOS 2002. The 15th Annual Meeting of the IEEE 2 516 517 vol.2 fdtd http://www.citeulike.org/user/dcastro/article/2762204 <i>Lasers and Electro-Optics Society, 2002. LEOS 2002. The 15th Annual Meeting of the IEEE, Vol. 2 (2002), pp. 669-670 vol.2.</i><br /><br />The FDTD method is used to design a InP photonic crystal (PC) waveguide filter operating at 1534 nm. The filter uses strong mode coupling effects which result in a small device area of 8 /spl mu/m /spl times/ 10 /spl mu/m. Design and simulation of a photonic crystal waveguide filter using the FDTD method MJ Cryan R Varrazza M Cowin M Hill IJ Craddock S Yu CJ Railton J Rorison Lasers and Electro-Optics Society, 2002. LEOS 2002. The 15th Annual Meeting of the IEEE, Vol. 2 (2002), pp. 669-670 vol.2. 2008-05-06T18:26:24-00:00 2002 Lasers and Electro-Optics Society, 2002. LEOS 2002. The 15th Annual Meeting of the IEEE 2 669 670 vol.2 design fdtd filter simulation http://www.citeulike.org/user/dcastro/article/2678815 <i>Microwave and Wireless Components Letters, IEEE, Vol. 18, No. 1. (2008), pp. 16-18.</i><br /><br />In this letter, we explore a general-purpose microstrip coupling model for computer aided design of new bandpass filters. The J-inverter topology of the model facilitates the study of coupling behaviours of different microstrip structures leading to a quick comparison of their coupling strengths. Based on such comparison, microstrip filters with interdigital capacitors and etched slots yielding relatively higher coupling coefficients are designed, fabricated and tested. The filters exhibit relatively wider bandwidths which are easily adjustable by way of changing the geometrical parameters of interdigital capacitors and slots. Adjustable Bandwidth Filter Design Based on Interdigital Capacitors Li Zhu V Devabhaktuni Chunyan Wang Ming Yu doi:10.1109/LMWC.2007.911975 Microwave and Wireless Components Letters, IEEE, Vol. 18, No. 1. (2008), pp. 16-18. 2008-04-16T19:38:04-00:00 2008 Microwave and Wireless Components Letters, IEEE 18 1 16 18 capacitor filter interdigital http://www.citeulike.org/user/dcastro/article/2674551 <i>Information Technology and Applications, 2005. ICITA 2005. Third International Conference on, Vol. 2 (2005), pp. 295-298 vol.2.</i><br /><br />Wideband mobile radio channel characteristics were measured in various environments in Korea. SKT conducted impulse response measurements at 2.3 GHz with a commercial channel sounder and presents multipath channel models for wireless local and metropolitan area networks. In this paper, we describe the process to analyze the measured data and build tapped delay line channel models. The whole measurements were conducted throughout more than 25 sites around Seoul city and various channel models that represents rural, suburban, suburban alternative, micro-cell hilly, urban high-rise and urban rooftop environments are presented. Multipath channel models for wireless local and metropolitan area networks K Jeong SH Kim KM Chung JC Kim JH Yu JS Lee SH Seo doi:10.1109/ICITA.2005.187 Information Technology and Applications, 2005. ICITA 2005. Third International Conference on, Vol. 2 (2005), pp. 295-298 vol.2. 2008-04-15T17:51:06-00:00 2005 Information Technology and Applications, 2005. ICITA 2005. Third International Conference on 2 295 298 vol.2 channel model multipath network wireless http://www.citeulike.org/user/dcastro/article/2135059 <i>Signals, Systems and Computers, 2003. Conference Record of the Thirty-Seventh Asilomar Conference on, Vol. 1 (2003), pp. 693-697 Vol.1.</i><br /><br />In this paper, we propose new channel estimation and equalization techniques for OFDM (orthogonal frequency division multiplexing) systems in mobile environment. In the mobile OFDM system, the estimation of time varying channel is the most important issue. In the proposed method, we assume that wireless channels are varying in the linear fusion during a certain internal, and estimate the initial channel coefficients and their corresponding slopes. After such estimation, we compensate the estimated channel and ICI (inter-carrier interference) effect due to time selectivity. We verify that this scheme shows better performance than conventional methods using computer simulations. Channel estimation and equalization for high speed mobile OFDM systems Heejung Yu Myung-Soon Kim Sok-Kyu Lee Signals, Systems and Computers, 2003. Conference Record of the Thirty-Seventh Asilomar Conference on, Vol. 1 (2003), pp. 693-697 Vol.1. 2007-12-17T06:51:10-00:00 2003 Signals, Systems and Computers, 2003. Conference Record of the Thirty-Seventh Asilomar Conference on 1 693 697 Vol.1 channel equalization estimation high mobile ofdm http://www.citeulike.org/user/dcastro/article/2067666 <i>Communications, 2007. ICC '07. IEEE International Conference on (2007), pp. 5720-5725.</i> On the Performance of IEEE 802.16 OFDMA System Under Different Frequency Reuse and Subcarrier Permutation Patterns H Jia Z Zhang G Yu P Cheng S Li Communications, 2007. ICC '07. IEEE International Conference on (2007), pp. 5720-5725. 2007-12-06T16:50:46-00:00 2007 Communications, 2007. ICC '07. IEEE International Conference on 5720 5725 80216 frequency ofdma