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    X-parameter-based modelling of polar modulated power amplifiers

    Wang, Y. ; Nielsen, T.S. ; Sira, D. ; Jensen, O.K. ; Larsen, T.
    Microwaves, Antennas & Propagation, IET

    Volume: 7 , Issue: 14
    Digital Object Identifier: 10.1049/iet-map.2012.0523
    Publication Year: 2013 , Page(s): 1161 - 1167

    IET Journals & Magazines

    X-parameters are developed as an extension of S-parameters capable of modelling non-linear devices driven by large signals. They are suitable for devices having only radio frequency (RF) and DC ports. In a polar power amplifier (PA), phase and envelope of the input modulated signal are applied at separate ports and the envelope port is neither an RF nor a DC port. As a result, X-parameters may fail to characterise the effect of the envelope port excitation and consequently the polar PA. This study introduces a solution to the problem for a commercial polar PA. In this solution, the RF-phase path is modelled by X-parameters and the envelope path of the polar PA is simulated by a low-pass filter. The solution can be applied to a group of polar PAs who have the similar topology and design as the one in this work. Modulated signals with different channel bandwidths were applied to the model of the polar PA for simulations. The simulated error vector magnitude (EVM) and adjacent channel power ratio (ACPR) were compared with the measured data to validate the model. The maximum differences between the simulated and measured EVM and ACPR are less than 2% point and 3 dB, respectively. View full abstract»

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    Practical considerations for high-power X-parameter measurements for power amplifier design

    Nielsen, T.S. ; Gillease, C. ; Torres, V.
    Wireless and Microwave Technology Conference (WAMICON), 2012 IEEE 13th Annual

    Digital Object Identifier: 10.1109/WAMICON.2012.6208473
    Publication Year: 2012 , Page(s): 1 - 9

    IEEE Conference Publications

    This paper presents a measurement system that is capable of characterizing and modeling high-power (>;250W) RF devices outside the standard 50Q environment. The system is based on the Agilent PNA-X and Nonlinear Vector Network Analyzer (NVNA) measurement platforms. It is configured for measurements on a commercially available 250W average output power Lateral Diffused Metal Oxide Semiconductor (LDMOS) technology power transistor from NXP. A number of practical considerations are described in the paper such as setup of the PNA-X pulse generators and RF modulators to provide adequate pulsed measurement conditions, NVNA power budget calculations to sustain PNA-X measurement receiver linearity requirements, and configuration of accurate in-pulse drain current measurements to ensure proper transistor drain efficiency calculations. Procedures for performing accurate high-power vector and NVNA phase and amplitude calibrations are also described as well as source-and load-pull measurement results and X-parameter modeling results on the 250W LDMOS power transistor. View full abstract»

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    Simulation and measurement-based X-parameter models for power amplifiers with envelope tracking

    Haedong Jang ; Zai, A. ; Reveyrand, T. ; Roblin, P. ; Popovic, Z. ; Root, D.E.
    Microwave Symposium Digest (IMS), 2013 IEEE MTT-S International

    Digital Object Identifier: 10.1109/MWSYM.2013.6697628
    Publication Year: 2013 , Page(s): 1 - 4

    IEEE Conference Publications

    Static X-parameter (XP) models for RF power amplifiers (PAs), derived from both simulations and nonlinear vector network analyzer (NVNA) measurements, are investigated for the prediction of PA performance under dynamic signal conditions such as in envelope tracking (ET). The instantaneous AM-AM, AM-PM and PAE predictions of XP models extracted from simulation are compared under ET dynamic signal conditions to two types of circuit models using envelope simulation. An XP PA model is extracted for a peak 8W GaN class-F-1 ET PA from NVNA measurements with automated bias control. By applying a constant gain shaping table derived from the XP model to the drain supply voltage, the average PAE is improved from 40% to 57% for 3.84 MHz WCDMA signals at 2.14 GHz compared to fixed drain bias operation. View full abstract»

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    Evaluation of envelope-domain dynamic X-parameter model based on variable-carrier-frequency analysis

    Yichi Zhang ; Maoliu Lin
    Millimeter Waves (GSMM), 2012 5th Global Symposium on

    Digital Object Identifier: 10.1109/GSMM.2012.6314044
    Publication Year: 2012 , Page(s): 236 - 240

    IEEE Conference Publications

    This paper studies the envelope-domain dynamic X-parameter model of RF power-amplifier nonlinear behavior. Based on the analysis of its fundamental assumptions and the main applications for inter-modulation predictions, the consideration of model sensibility to variable carrier-frequency is proposed as one criterion to evaluate the reasonableness of the mathematical modeling. The experimental results in this paper show that the dynamic X-parameters are compatible with each other only within a small neighborhood around the desired carrier frequency, which on one hand may to some extent reflect the reasonableness of the theory, and on the other hand serve to investigate the validity and limits of dynamic X-parameters from a new perspective. View full abstract»

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    X-parameter-based frequency doubler design

    Jialin Cai ; Brazil, T.J.
    Microwave Conference (EuMC), 2012 42nd European

    Publication Year: 2012 , Page(s): 1174 - 1177

    IEEE Conference Publications

    As a kind of superset of S-parameters, X-parameters are becoming increasingly popular in non-linear device simulation and measurement. Due to their good accuracy and convenient extraction procedures, X-parameter-based transistor device models have so far been mainly used in power amplifiers design. They have been limited to this kind of design up to now because the X-parameter models extracted are only suitable for fundamental frequency circuit design. In this paper, a new extraction method is described to allow the extracted model to be used to designing a frequency doubler, and verification through simulation results is presented. View full abstract»

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    Down-converted mixer verification using the measured X-parameter for system engineering designers

    Hsu-Feng Hsiao ; Chih-Ho Tu ; Hann-Huei Tsai ; Hsu-Chen Cheng ; Da-Chiang Chang ; Ying-Zong Juang
    Microwave Conference Proceedings (APMC), 2013 Asia-Pacific

    Digital Object Identifier: 10.1109/APMC.2013.6694956
    Publication Year: 2013 , Page(s): 854 - 856

    IEEE Conference Publications

    This paper investigates the down-converted mixer verification using the measured X-parameter in future system-level simulation. The X-parameter measurement system utilizing Agilent's nonlinear vector network analyzer (NVNA) and the external RF signal generator can provide the desired stimulus to device under test (DUT) at the specified port in order to measure and respond to the non-linear DUT characteristic. The X-parameter of the down-converted mixer may include the measured nonlinear output power and phase at the specified frequencies. Also, the down-converted mixer utilizing nonlinear device characteristic to convert RF to intermediate frequency (IF) can be described by the X-parameter with good consistency. View full abstract»

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    X-parameter techniques for signal integrity in high-speed links

    Schutt-Aine, J. ; Comberiate, T.
    Electronics Packaging Technology Conference (EPTC 2013), 2013 IEEE 15th

    Digital Object Identifier: 10.1109/EPTC.2013.6745719
    Publication Year: 2013 , Page(s): 235 - 239

    IEEE Conference Publications

    X-parameters have been shown to have a wide array of applications in the modeling of nonlinear devices and systems. In this work we demonstrate that they can be combined with LIM and IBIS to produce robust models for high-speed links. In particular IBIS data generation from X parameters is demonstrated and its advantage over currently available methods is discussed. View full abstract»

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    X-parameter-based frequency doubler design

    Jialin Cai ; Brazil, T.J.
    Microwave Integrated Circuits Conference (EuMIC), 2012 7th European

    Publication Year: 2012 , Page(s): 794 - 797

    IEEE Conference Publications

    As a kind of superset of S-parameters, X-parameters are becoming increasingly popular in non-linear device simulation and measurement. Due to their good accuracy and convenient extraction procedures, X-parameter-based transistor device models have so far been mainly used in power amplifiers design. They have been limited to this kind of design up to now because the X-parameter models extracted are only suitable for fundamental frequency circuit design. In this paper, a new extraction method is described to allow the extracted model to be used to designing a frequency doubler, and verification through simulation results is presented. View full abstract»

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    On wafer X-parameter based modeling of a switching cascode power amplifier

    Yelin Wang ; Sira, D. ; Nielsen, T.S. ; Jensen, O.K. ; Larsen, T.
    NORCHIP, 2011

    Digital Object Identifier: 10.1109/NORCHP.2011.6126705
    Publication Year: 2011 , Page(s): 1 - 4

    IEEE Conference Publications

    X-parameters have been introduced as the natural extension of S-parameters capable of characterizing a nonlinear device excited by a large-signal input. This paper describes validation of the X-parameter model of a switching cascode power amplifier (PA), which has strong nonlinearity. The X-parameter model of the PA was measured and extracted by an Agilent N5245A PNA-X. Measurements were done on wafer and deem-bedded to the input and output pads of the device. An Enhanced Data rates for GSM Evolution (EDGE) signal was applied to the model for simulations. The simulated relative levels of output spectrum and RMS value of error vector magnitude (EVM) were compared with the measured data in order to validate the X-parameter model. A good match was achieved between the simulation and measurement. The maximum difference between the simulated and measured relative levels of output spectrum is 4 dB. The maximum error between the simulated and measured EVM is less than 3 %-point. View full abstract»

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    Implementation of X-parameter models in harmonic-balance simulators

    Soury, Arnaud ; Ngoya, E.
    Microwave Symposium Digest (MTT), 2012 IEEE MTT-S International

    Digital Object Identifier: 10.1109/MWSYM.2012.6258278
    Publication Year: 2012 , Page(s): 1 - 3
    Cited by:  Papers (1)

    IEEE Conference Publications

    X-parameter modeling paradigm constitutes a major advancement in circuit and system simulation and design. However being a frequency domain defined nonlinear model, its implementation in harmonic-balance simulators is not trivial. The implementation available in commercial simulators does not fully respond to the needs. In particular, the multi-tone simulations and the prediction of the dynamic effects remain challenges. This paper presents a method to implement such behavioral models into the RF engines. Despite the fact that this paper covers the implementation of X-parameter model, it's perfectly applicable to any behavioral models describing the relations between complex envelope signals. View full abstract»

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    X-Parameter Measurement and Simulation of a GSM Handset Amplifier

    Horn, J.M. ; Verspecht, J. ; Gunyan, Daniel ; Betts, L. ; Root, D.E. ; Eriksson, J.
    Microwave Integrated Circuit Conference, 2008. EuMIC 2008. European

    Digital Object Identifier: 10.1109/EMICC.2008.4772247
    Publication Year: 2008 , Page(s): 135 - 138
    Cited by:  Papers (11)

    IEEE Conference Publications

    X-parameters, also referred to as the parameters of the Poly-Harmonic Distortion (PHD) nonlinear behavioral model, have been introduced as the natural extension of S-parameters to nonlinear devices under large-signal drive [1]-[3]. This paper describes a new approach to X-parameter characterization and nonlinear simulation - including large-signal experimental model validation - of a commercially available GSM amplifier. A specially configured Nonlinear Vector Network Analyzer (NVNA) and procedure for measuring, for the first time, X-parameters under pulsed bias conditions is presented. The measured pulsed bias X-parameters are then used with the PHD framework to enable accurate nonlinear simulation of device behavior, including harmonics (magnitude and phase) under pulsed bias large-signal conditions with mismatch. Independent NVNA measurements validate the predictions of the X-parameter simulations of output match under drive, and show the inadequacy of "Hot S22" techniques to predict such device performance. View full abstract»

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    Nonlinear validation of arbitrary load X-parameter and measurement-based device models

    Gunyan, Daniel ; Horn, J. ; Jianjun Xu ; Root, D.E.
    Microwave Measurement Conference, 2009 73rd ARFTG

    Digital Object Identifier: 10.1109/ARFTG.2009.5278063
    Publication Year: 2009 , Page(s): 1 - 4
    Cited by:  Papers (7)  |  Patents (1)

    IEEE Conference Publications

    X-parameters are the mathematically correct supersets of S-parameters valid for nonlinear (and linear) components under large-signal (and small-signal) conditions. This paper compares a PHD model generated from arbitrary load-dependent measured X-parameters and a measurement-based non-quasi-static device model and validates them against tuned-load measurements. CW, IMD, and ACPR swept-power measurements are compared. The models agree on the simulated device behavior and compare well to validation measurements. View full abstract»

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    X-parameter measurement challenges for unmatched device characterization

    Bespalko, Dylan T. ; Boumaiza, S.
    Microwave Measurements Conference (ARFTG), 2010 75th ARFTG

    Digital Object Identifier: 10.1109/ARFTG.2010.5496317
    Publication Year: 2010 , Page(s): 1 - 4
    Cited by:  Papers (2)

    IEEE Conference Publications

    X-parameter technology provides simulation-based design of non-linear circuits with inherent accuracy that is attributed to measurement-based model extraction. Recent advancements have combined Non-linear Vector Network Analyzer measurements with impedance tuners to compliment the equivalent accuracy of load-pull measurements with the analytic convenience of equation-based large-signal models. This paper investigates the challenges incurred when modeling high-power transistors under variable complex impedance matching conditions. It also compares the predicted performance of the X-parameter model against an independent large-signal model provided by the manufacturer for a 10W transistor. The results show a good correlation between the two models when compared under load-pull impedance modulation. View full abstract»

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    Compact behavioral description for generalized loads using a modified DC X-parameter model

    Jialin Cai ; Brazil, T.J.
    Wireless Symposium (IWS), 2013 IEEE International

    Digital Object Identifier: 10.1109/IEEE-IWS.2013.6616769
    Publication Year: 2013 , Page(s): 1 - 4

    IEEE Conference Publications

    A modified DC X-parameter model is presented. The model gives much better accuracy than a basic 50 Ω DC X-model. Compared with a full load-pull DC X-model, the presented model not only greatly decreases the model's file-size, but also provides comparably good accuracy. The optimization of the model is also presented, and based on this method both the model extraction time and the file-size are further improved. View full abstract»

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    Handling long-term memory effects in X-parameter model

    Soury, Arnaud ; Ngoya, E.
    Microwave Symposium Digest (MTT), 2012 IEEE MTT-S International

    Digital Object Identifier: 10.1109/MWSYM.2012.6257768
    Publication Year: 2012 , Page(s): 1 - 3
    Cited by:  Papers (1)

    IEEE Conference Publications

    Since the last decade, the behavioral modeling of RF functional blocks (amplifiers, mixers, (de)modulators, etc.) has been a flourishing research domain that has led to a better overall understanding of the nonlinear dynamics impact to the circuit performances. Recently the X-parameter paradigm has been introduced. The formalism provides a comprehensive description of the relationships between all the harmonics of the scattered and incident power waves at the ports of a device, and represents a major advancement in RF circuit characterization. The formalism however still needs effective handling of the long term memory effects. In this paper, a simple and efficient approach is proposed to model long-term memory effects within X-parameter. It ensures both a simple extraction procedure and an efficient numerical implementation. View full abstract»

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    X-parameter measurement and simulation of an RF amplifier designed to drive a comb-generator

    Xin Dongdong ; Lin Maoliu
    Electronic Measurement & Instruments (ICEMI), 2011 10th International Conference on

    Volume: 1
    Digital Object Identifier: 10.1109/ICEMI.2011.6037673
    Publication Year: 2011 , Page(s): 37 - 39

    IEEE Conference Publications

    X- parameters, referred to as the parameters of the Poly-Harmonic Distortion (PHD) nonlinear behavioral model as well, have been introduced as the natural extension of S-parameters to nonlinear devices under large-signal drive. This paper describes the approach and procedure of X-parameter characterization and nonlinear simulation of an RF amplifier designed to drive a comb-generator, including measurement experiment, modeling, and model validation. Firstly, a specially configured Nonlinear Vector Network Analyzer (NVNA) is used to the measurements. Secondly, the X-parameters are extracted. Then the parameters are used with the X-parameter framework in ADS to enable accurate nonlinear simulation of device behavior. Independent NVNA measurements validate the model predictions, and show the inadequacy of `Hot S22' in predicting such performance. View full abstract»

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    A scalable X-parameter model for GaAs and GaN FETs

    Leckey, J.G.
    Microwave Integrated Circuits Conference (EuMIC), 2011 European

    Publication Year: 2011 , Page(s): 13 - 16
    Cited by:  Papers (2)

    IEEE Conference Publications

    A new nonlinear FET model formulation is proposed which comprises an X-parameter (S-function or Poly Harmonic Distortion) intrinsic model combined with lumped extrinsic circuit model shells This enables the correct gate width scaling of the intrinsic and extrinsic model by finger number and unit gate width. An extraction technique is described based on de-embedding the X-parameters to the intrinsic plane. A verification example of scaling of a 10×90um 0.15um pHEMT X-parameter model (generated from a scalable compact model) down to a 4×50um device (a factor of 4.5), is shown without loss of accuracy in power sweep and loadpull contour results compared to the reference compact model simulation. View full abstract»

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    Simulation of a power amplifier used for TD-SCDMA mobile terminal

    Haiying Jiang ; Yougang Gao ; Wei Dong ; Di Liu
    Cross Strait Quad-Regional Radio Science and Wireless Technology Conference (CSQRWC), 2011

    Volume: 1
    Digital Object Identifier: 10.1109/CSQRWC.2011.6037023
    Publication Year: 2011 , Page(s): 606 - 610
    Cited by:  Papers (2)

    IEEE Conference Publications

    In this paper, a PA (Power Amplifier) used for TD-SCDMA terminal is simulate and measured, and the simulation results are verified by measurement results. Firstly, PHD (Poly-Harmonic Distortion) nonlinear behavioral model, which is referred to as X-parameters, of the PA extracted from Agilent NVNA (Nonlinear Vector Network Analyzer) measurement is imported to Agilent ADS (Agilent Advance Design System) to simulate its performance and distortion under TD-SCDMA signal stimulation, which is referred to as PHD model simulation. Secondly, the TD-SCDMA signal used for PHD model simulation is downloaded into the Agilent E4438C signal generator to be as the input for PA during measurement. Thirdly, the signal output from PA is caught and recorded by Vector Signal Analyzer under control of 89600 vector Signal analyzer software, and the signal recorded is imported to ADS to be analyzed by the same method used in PHD model simulation. At last, results such as output power, available gain, spectrum, ACPR (Adjacent Channel Power Ratio), RMS (Root Mean Square) EVM (Error Vector Magnitude) and signal constellation from PHD model simulation and measurement are compared, and it can be found that the PHD model simulation results agree very well with measurement results. As a result, the simulation method designed in this paper can be used to evaluate PA performance and PA distortion correctly. View full abstract»

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    Padé-approximation-based behavioral modeling

    Jialin Cai ; Brazil, T.J.
    Microwave Symposium Digest (IMS), 2013 IEEE MTT-S International

    Digital Object Identifier: 10.1109/MWSYM.2013.6697491
    Publication Year: 2013 , Page(s): 1 - 3

    IEEE Conference Publications

    A new nonlinear black-box, frequency-domain model is presented in this paper, based on the Padé approximation theory. The Padé model is similar in concept to the X-parameter model. Comparisons between the ADS X-parameter model and the Padé model are presented here. Based on the simulation results, it is shown that the new Padé nonlinear model has generally better accuracy than the X-parameter model without introducing any additional complexity. View full abstract»

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    Electrothermal behavioral model identification and validation from time domain load pull measurement of a RF power amplifier

    Besombes, Florent ; Ngoya, E. ; Mazeau, J. ; Sommet, R. ; Monsy, Sebastien ; Martinaud, Jean-Paul
    Microwave Symposium Digest (MTT), 2012 IEEE MTT-S International

    Digital Object Identifier: 10.1109/MWSYM.2012.6259489
    Publication Year: 2012 , Page(s): 1 - 3

    IEEE Conference Publications

    This paper presents a behavioral model for RF power amplifiers including load-pull and self-heating effects for radar applications. The model topology combines nonlinear scattering functions with a thermal model. This work focuses on model identification from time domain load-pull measurements and thermal simulations of the power amplifier. Comparisons between model and pulsed measurements, demonstrate its ability to accurately reproduce the signals and temperature for arbitrary load impedances. View full abstract»

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    Advances in linear and non-linear modeling for improved microwave design

    Dunleavy, L. ; Weller, Thomas ; Jiang Liu ; Morales, H. ; Skidmore, S.
    Wireless and Microwave Technology Conference (WAMICON), 2012 IEEE 13th Annual

    Digital Object Identifier: 10.1109/WAMICON.2012.6208478
    Publication Year: 2012 , Page(s): 1 - 5

    IEEE Conference Publications

    This paper addresses two areas of improvement to microwave linear and non-linear modeling. The first area concerns best-practice application examples of electromagnetic (EM) analysis combined with accurate broad-band parasitic models for improved board-based designs using surface mount components. The focus is on co-simulation - which combines circuit and EM simulation - of surface mount capacitors in shunt configurations. The second area that is covered in this paper is to study the X-parameter modeling technique used in characterizing nonlinear devices compared to traditional compact modeling technique. The results show that X-parameter models can be helpful for compact model validation and can also provide a good alternative to compact models for specific devices and operating conditions. View full abstract»

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    An analytical approach to obtain optimum load impedance using X-parameters®

    Zargar, H. ; Banai, A. ; Cai, J. ; Brazil, T.
    Integrated Nonlinear Microwave and Millimetre-Wave Circuits (INMMIC), 2012 Workshop on

    Digital Object Identifier: 10.1109/INMMIC.2012.6331931
    Publication Year: 2012 , Page(s): 1 - 3

    IEEE Conference Publications

    This paper introduces an analytical approach to obtain fundamental and harmonic load-pull contours using X-parameters. This method is proposed to obtain the optimum load impedance at different harmonics. This approach has been applied on a two port X-parameter model and its results are independently verified by ADS simulation. View full abstract»

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    Velocity retrieval of moving object from a single channel high resolution SAR data

    Jeong-Won Park ; Joong-Sun Won
    Synthetic Aperture Radar (APSAR), 2011 3rd International Asia-Pacific Conference on

    Publication Year: 2011 , Page(s): 1 - 4

    IEEE Conference Publications

    Two-dimensional velocity retrieval methods from a single channel high resolution SAR data through a joint time-frequency analysis and a fractional Fourier transform (FrFT) are presented. Two-dimensional velocity can be measured by estimation of the Doppler center frequency and Doppler frequency rate for the range and azimuth velocity component, respectively. The Doppler spectrum along a Doppler phase history line in the time-frequency domain was reconstructed and projected onto the frequency and time dimension. The peak of the frequency-axis projected spectrum corresponds to the Doppler center frequency, while that of the time-axis indicates an azimuth time of closest approach. The Doppler frequency rate is also measured by the slope deviation of the Doppler spectrum. Simulation using TerraSAR-X parameters indicated that the velocity errors were less than 1 m/sec or 5% for moving objects with a velocity higher than 3 m/sec. While the measurement of Doppler center frequency was reliable over the entire velocity range, errors in Doppler frequency rate became large if the velocity was lower than 3 m/sec. An experiment using TerraSAR-X and truck-mounted corner reflectors validated the measurement accuracy of the approach. Absolute and percent errors of the range velocity were 1.4 km/h and 2.8%, respectively, while the azimuth velocity measurement was comparatively accurate under an assumption of zero acceleration. To apply the method to single-look complex data, the full Doppler bandwidth must be preserved. Application of a fractional Fourier transform (FrFT) to the same data is also presented. The FrFT approach significantly improves computational efficiency and is superior to the WVD approach in estimation of Doppler frequency rate. View full abstract»

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    Using the latency insertion method (LIM) to generate X parameters

    Comberiate, T.M. ; Schutt-Aine, J.E.
    Electrical Performance of Electronic Packaging and Systems (EPEPS), 2012 IEEE 21st Conference on

    Digital Object Identifier: 10.1109/EPEPS.2012.6457896
    Publication Year: 2012 , Page(s): 280 - 283
    Cited by:  Papers (2)

    IEEE Conference Publications

    X parameters have been shown to have a wide array of applications in the modeling of nonlinear devices and systems. In this work, the polyharmonic distortion (PHD) model and the latency insertion method (LIM) are combined to generate X parameters describing the nonlinear relationship between power waves. This technique leverages the speed and convergence advantages of the LIM simulation method to generate frequency-domain models. Results are compared with those of other methods. View full abstract»

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    New Trends for the Nonlinear Measurement and Modeling of High-Power RF Transistors and Amplifiers With Memory Effects

    Roblin, P. ; Root, D.E. ; Verspecht, J. ; Ko, Y. ; Teyssier, J.P.
    Microwave Theory and Techniques, IEEE Transactions on

    Volume: 60 , Issue: 6 , Part: 2
    Digital Object Identifier: 10.1109/TMTT.2012.2193140
    Publication Year: 2012 , Page(s): 1964 - 1978
    Cited by:  Papers (2)

    IEEE Journals & Magazines

    Power amplifier (PA) behavior is inextricably linked to the characteristics of the transistors underlying the PA design. All transistors exhibit some degree of memory effects, which must therefore be taken into account in the modeling and design of these PAs. In this paper, we will present new trends for the characterization, device modeling, and behavioral modeling of power transistors and amplifiers with strong memory effects. First the impact of thermal and electrical memory effects upon the performance of a transistor will be revealed by comparing continuous wave and pulsed RF large-signal measurements. Pulsed-RF load-pull from the proper hot bias condition yields a more realistic representation of the peak power response of transistors excited with modulated signals with high peak-to-average power ratio. Next, an advanced device modeling method based on large-signal data from a modern nonlinear vector network analyzer instrument, coupled with modeling approaches based on advanced artificial neural network technology, will be presented. This approach enables the generation of accurate and robust time-domain nonlinear simulation models of modern transistors that exhibit significant memory effects. Finally an extension of the X-parameter (X-parameter is a trademark of Agilent Technologies Inc.) behavioral model to account for model memory effects of RF and microwave components will be presented. The approach can be used to model hard nonlinear behavior and long-term memory effects and is valid for all possible modulation formats for all possible peak-to-average ratios and for a wide range of modulation bandwidths. Both the device and behavioral models have been validated by measurements and are implemented in a commercial nonlinear circuit simulator. View full abstract»

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