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We investigated the measurement techniques of the nonlinear vector network analyzer (NVNA) test bench, to fully characterize the nonlinear behavior of radio frequency (RF) power amplifiers (PAs) driven by complex modulated signals. In order to extend the baseband measurements, two kinds of NVNA phase reference approaches are developed as alternative solutions, so that the baseband phase measurements can be achieved with those of modulated components at multiharmonic RF bands. In the first approach, a modulated baseband signal is combined with another modulated RF one to become the desired NVNA phase reference. While as an alternative solution, the second phase reference design is based on a “stepped” multisine, which is stepped through the baseband and each harmonic following the NVNA swept measurements, to achieve stable phase measurements. To validate these proposed NVNA test bench designs, an RF PA, driven by a large-signal long-term evolution-like multisine, was tested and compared with digital real-time oscilloscope measurements. [ABSTRACT FROM PUBLISHER]

This paper presents novel nonlinear vector network analyzer (NVNA)-based techniques for characterizing the harmonic and intermodulation nonlinearity of dual-band radio frequency (RF) power amplifiers (PAs). On the one hand, a wideband Schroeder-phase multisine is used to drive a step recovery diode comb generator, so that a novel multiharmonic-band NVNA phase reference on a dense spectral grid is obtained. On the other hand, a novel phase calibration approach is developed to synchronize the NVNA multiband measurements. To validate the NVNA testbed with novel techniques, an RF PA under two typical kinds of dual-band multisine stimulus is tested, where the NVNA measurement is compared with that of an oscilloscope. This paper can be easily adapted for various multiband conditions. [ABSTRACT FROM PUBLISHER]

This paper presents a novel realization of nonlinear vector network analyzer (NVNA) test-bed with a new phase calibration technique, in order to characterize the multiharmonic intermodulation nonlinearity of a radio frequency (RF) power amplifier (PA) under a large-signal modulated input. The NVNA test-bed uses a step recovery diode comb generator as the phase reference, which is driven by a pulsed-RF signal with a high duty cycle of over 99%. Hence all the multiharmonic intermodulation tones of interest can be measured at once. A multisine phase standard provided by a vector signal analyzer is used to calibrate the intermodulation tones at each harmonic on a dense spectral grid. Two harmonic phase standards with different fundamental frequencies are used to synchronize the phase calibration results at different harmonics. The validity of this paper is verified by comparing NVNA measurements with oscilloscope measurements of the same PA under test. This paper can be used to inspect the nonlinearity of RF amplifiers under large-signal modulated excitations in both the frequency and time domains. [ABSTRACT FROM AUTHOR]

This paper proposes a practical approach for dense-spectral-grid phase measurements based on a nonlinear vector network analyzer (NVNA). With the multitone outputs of commercial VSGs as both phase references and standards, a modified NVNA is presented to effectively obtain the phase spectra of modulated RF signals with spectral resolution of 1–100 kHz. Due to the limited tone number of a VSG multitone standard, a multistep phase calibration method is also proposed in this paper for multiplying the calibratable tone numbers in practice. A phase accuracy of ±2° has been experimentally achieved with both the VSG-based approach and the multistep phase calibration method at 2.4 GHz on a 1–100-kHz spectral grid. [ABSTRACT FROM AUTHOR]