Characterizing Amplifier Modulation Distortion Using a Vector Network Analyzer

Verspecht, Jan; Stav, Augustine; Teyssier, Jean-Pierre; Kusano, Sam

doi:10.1109/arftg.2019.8739226

Cited by 36 publications

(11 citation statements)

References 2 publications

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“…In this respect, the secants' method shows better performance in terms of convergence speed, given that the number of iterations is comparable to the other methods despite the distortion-induced mutual couplings among the tones, while the number of evaluations is significantly less. The independence of the number or evaluations from the number of tones in secants' case is particularly significant when considering broadband standardlike excitations, as multitones test signals with hundreds or thousands of tones are required to approximate the original standard to a good degree of accuracy [8], [11], [13], [16], [17].…”

Section: Walp Methods' Comparisonmentioning

confidence: 99%

“…Indeed, periodic multitone signals can be designed to mimic the statistical and spectral properties of communication standards [11]. Among the many different techniques available in literature [8], [11]- [13], flat-amplitude random-phase multitones with a prescribed BW will be used in this work to provide a close approximation of complex-gaussian envelope of 5G-OFDM waveforms.…”

Section: Problem Statementmentioning

confidence: 99%

“…Nevertheless, the setup is capable of working up to the full BW of the instrument front-ends, with arbitrarily narrow tone spacing. These characteristics are typically required in order to perform WALP using multitone signals featuring a good statistical and spectral approximation of the target telecom signal envelope [8], [12], [17]. In the proposed setup, the minimum achievable tone spacing is ultimately limited by the maximum allowed measurement time, available instrument memory, source phase noise, and thermal drifts.…”

Section: Measurement Setupmentioning

confidence: 99%

“…The value of the LS multitone Γ out is shown to depend on the actual phase realization of the multitone, and it is significantly different from its SS value. Nevertheless, the statistical uncorrelatedness of the different frequencies in the input signal allows to average the LS Γ out measured with the multitone method across adjacent bins [8]. In this way, the smoothed profile (referred to as smooth Γ out in Fig.…”

Section: Estimation Of the Large-signal Output Matchmentioning

confidence: 99%

“…Moreover, it removes the need of single-shot demodulation of large instantaneous BWs, enabling WALP on the much wider excitation BWs required by modern communication standards. Thanks to these novel capabilities, several VNA-based advanced PA measurements, such as wideband modulation distortion [8]- [10], can be performed directly at transistor level. Indeed, the VNA-WALP proposed in this work allows to emulate the output termination conditions seen in the final application, without needing any detailed knowledge of the modulated loadline.…”

mentioning

confidence: 99%

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Wideband Active Load–Pull by Device Output Match Compensation Using a Vector Network Analyzer

Angelotti

Gibiino

Nielsen

et al. 2021

IEEE Trans. Microwave Theory Techn.

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This work investigates wideband active load-pull (WALP) on microwave electron devices with a standard vector network analyzer (VNA), solely using calibrated frequencydomain relative measurements. Differently from the methods requiring full time-domain waveform acquisition capabilities, this approach removes any instantaneous bandwidth (BW) requirement, allowing to target modulated signals with arbitrarily large BWs. A VNA-based measurement setup is presented, and a novel mathematical framework is developed in order to enable the synthesis of an arbitrary wideband load profile using suitable numerical algorithms. A linear pre-compensation of the LS output match of the device, here implemented by different methods, is shown to significantly improve the speed and the stability of the basic secants' iterative method used to reach the target. Performance results, investigating the convergence properties of the approach and the effects of the setup dynamic range, are reported for a Gallium Nitride (GaN) high-electronmobility-transistor (HEMT) for up to 120-MHz output BW in the sub-6 GHz range.Index Terms-Active load-pull, modulated signals, power amplifiers, vector network analyzer, device characterization. I. INTRODUCTIONT HE ever-growing demand for high data rates in modern mobile communication standards, e.g., 5G, requires the operation of power amplifiers (PA) in radio frequency (RF) transmitters across extremely wide bandwidths (BWs), i.e., tens or hundreds of MHz. In this respect, novel characterization techniques are required to evaluate the behaviour of electron devices used in PA circuits under operating conditions that closely approximate typical telecom applications. Wideband active load-pull (WALP) has been proposed as a promising technique to characterize microwave transistors and to optimize PA performance using excitations that mimic typical communication standards [1]-[4]. The method allows to set, for a given device-under-test (DUT), a user-prescribed load reflection coefficient profile across a wide modulation BW at fundamental and harmonic frequencies. The approach, at the cost of increased complexity, overcomes the main disadvantages of traditional passive load-pull. WALP can provide full coverage of the Smith Chart compensating for insertion loss, and can extend the narrow relative BW due to delay

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Section: Walp Methods' Comparisonmentioning

confidence: 99%

Section: Problem Statementmentioning

confidence: 99%

Section: Measurement Setupmentioning

confidence: 99%

Section: Estimation Of the Large-signal Output Matchmentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Wideband Active Load–Pull by Device Output Match Compensation Using a Vector Network Analyzer

Angelotti

Gibiino

Nielsen

et al. 2021

IEEE Trans. Microwave Theory Techn.

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show abstract

Spectrum Analysis

2020

Handbook of Microwave Component Measurements

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Nonlinear noise spectrum measurement using a probability-maintained noise power ratio method

Zhang

et al. 2022

Commun Eng

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Nonlinear distortion (noise) limits many communication systems, demanding a means of estimating system performance via device nonlinear characteristics. The noise power ratio (NPR) method which was proposed in 1971 solves this problem for systems with Gaussian stimuli or with special nonlinearity, but practical and accurate methods for many communication systems with non-Gaussian stimuli are rare. Here we propose a probability-maintained (PM) NPR method to accurately measure the spectrum of nonlinear noise via a spectrum analyzer in non-specific systems, including systems with non-Gaussian stimuli. Using an equivalent additive noise model in which the spectrum of equivalent nonlinear noise is the measurement result of PM NPRs, nonlinear system performance could be estimated with an error of 0.5 dB. Further, we find that zero-mean Chi-square noise, instead of Gaussian noise, should be selected for large memory and low-order nonlinear systems. Our method is verified in seven different scenarios with various nonlinear mechanisms and communication applications.

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Characterizing Amplifier Modulation Distortion Using a Vector Network Analyzer

Cited by 36 publications

References 2 publications

Wideband Active Load–Pull by Device Output Match Compensation Using a Vector Network Analyzer

Wideband Active Load–Pull by Device Output Match Compensation Using a Vector Network Analyzer

Spectrum Analysis

Nonlinear noise spectrum measurement using a probability-maintained noise power ratio method

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