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Session: TH3E1:20 PM Thursday, June 19, 2008 Room: A315/316 |
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Session: TH3E | Nonlinear circuit analysis and system simulation |
Chair: | José Carlos Pedro, Institute of Telecommunications - University of Aveiro |
Co-Chair: | Vittorio Rizzoli, DEIS - University of Bologna |
Abstract: | The session introduces a wealth of innovative techniques for nonlinear circuit, component, and system modeling, simulation, and design. The topics covered range from power-amplifier behavioral modeling to microwave link analysis under realistic propagation conditions. |
| | TH3E-01 | A CAD Procedure for MIMO Link Estimation by the Combination of Nonlinear, Electromagnetic and Propagation Analysis Techniques | 1414 | V. Rizzoli, A. Costanzo, P. Spadoni, F. Donzelli, D. Masotti, E. M. Vitucci, University of Bologna, Bologna, Italy |
| The paper demonstrates for the first time a CAD procedure for the circuit-level simulation of an entire MIMO link. The multiple transmitting and receiving antennas are treated as multiport radiating systems characterized by EM analysis. In this way the influence of mutual couplings on the frequency-dependent near-field and far-field performance of each element is fully accounted for. The set of transmitters is treated as a unique nonlinear system loaded by the multiport antenna, and is analyzed by nonlinear circuit techniques. In order to establish the connection between transmitters and receivers, the far fields incident on the receivers are evaluated by EM analysis and are combined by extending to the MIMO case an available ray tracing technique. EM theory is used to describe the receiving array as a linear active multiport network. The procedure is applied to several MIMO systems by varying antenna locations. The computation of BER performance at the circuit level is demonstrated. | | |
TH3E-02 | Quantifying Distortion of RF Power Amplifiers for Estimation of Predistorter Performance | 1622 | P. J. Draxler1, A. Zhu3, J. J. Yan2, P. Kolinko2, D. F. Kimball2, P. M. Asbeck2, 1Qualcomm Inc & UCSD, San Diego, United States, 2University of California, San Diego, La Jolla, United States, 3University College Dublin, Dublin, Ireland |
| This paper demonstrates a method to quantify the accuracy of memory models and the effectiveness of digital predistortion of power amplifiers with memory. By using assumptions of periodic stationarity, coherent ensemble averaging and a stable measurement system, we are able to decompose the waveform distortion into memoryless, deterministic memory, and random memory contributions. We demonstrate how this can be used to evaluate the performance of a power amplifier and project its optimal performance with predistortion. We also show that the dynamic deviation reduction-based Volterra series digital predistortion technique converges to the optimal performance for an experimental class AB power amplifier implemented with GaN FETs. | | |
TH3E-03 | A Linearized Polar Transmitter for Wireless Applications | 1477 | P. M. Cabral1, J. C. Pedro1, J. A. Garcia2, L. Cabria2, 1Universidade de Aveiro, Aveiro, Portugal, 2Universidad de Cantabria, Santander, Spain |
| This paper reports on a new design method to overcome the nonlinear distortion associated to polar transmitters. The proposed methodology complements the modulation of drain bias, vDD(t), of conventional envelope elimination and restoration power amplifiers with a proper variation of the input drive level, vg(t). Allowing vg(t) to vanish when vDD(t) goes to zero, it obviates the inherent nonlinear distortion caused by the amplifier carrier feed-through. In addition, and beyond guaranteeing linear operation, such a design methodology is also beneficial for power added efficiency as it prevents the dissipation of instantaneous input power for a desired null instantaneous output power. | | |
TH3E-04 | Mismatch Detection and Compensation Algorithm with the Closed Form Solution for the LINC System Implementation | 1188 | S. Myoung1, I. Lee2, K. Lim3, J. Yook1, J. Laskar3, 1Yonsei University, Seoul, Republic of Korea, 2Kongju National University, Kongju, Republic of Korea, 3Georgia Institude of Technology, Atlanta, United States |
| This paper proposes a path mismatch detection and compensation algorithm with the closed form solution for LInear Amplification with Non-linear Components (LINC) system implementation. The LINC system has a merit of using the high efficient amplifier. However, the performance degradation is extremely sensitive to the path mismatch such as amplitude as well as phase mismatch of transfer functions of two signal paths. In this work, a method with the closed form solution is developed that predicts the exact mismatch value without iterations. The LINC system is realized with the proposed mismatch detection and compensation algorithm. The performance was evaluated using the IEEE 802.16 WiMAX sinal, which has 7 MHz channel bandwidth and 16-QAM. The Error Vector Magnitude (EVM) of -37.37 dB was obtained through performance test, which meets performance requirement of -24 dB EVM. | | |
TH3E-05 | Implementation of a Volterra Behavioral Model for System Simulation | 1048 | S. A. Maas1, J. Pedro2, 1Applied Wave Research, Long Beach, United States, 2Institute of Telecommunications, University of Aveiro, Aveiro, Portugal |
| This paper describes a behavioral model based on Volterra series, for use in a time-domain system simulator. Model identification is implemented by harmonic balance analysis of the modeled circuit, generating frequency-domain transfer functions, which are converted to time-domain kernels. The high efficiency model identification process minimizes computational effort, resulting in a highly practical methodology. | | |
TH3E-06 | Nonlinear analysis and design of frequency selective limiters based on parametric circuits | 1561 | F. Ramirez1, R. Melville2, A. Suarez1, J. S. Kenney3, 1University of Cantabria, Santander, Spain, 2New Jersey Institute of Technology, Newark, United States, 3Georgia Institute of Technology , Atlanta, United States |
| A parametric circuit based on varactor-diodes is presented for its application as a frequency-selective limiter. A simplified analytical model is initially derived for a general understanding of the circuit performance. The power limitation is due to the frequency division of above threshold signals, leading to a reduction of the output power. Next harmonic-balance simulation is applied to analyze the limiter behavior in the presence of a strong and a weak signal. A matching technique is derived to increase the input-power range with high limitation level. Cascaded detuned stages are used to limit multiple above threshold signals. An in-depth analysis of the behavior under two interferers is also presented, showing that each stage enables the frequency division of a different interferer. The techniques have been successfully applied to a frequency selective limiter in the 850 MHz band. | | |
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