“Hybrid” approach to microwave power amplifier design
ABSTRACT A new “hybrid” approach to microwave power amplifier design is presented which is based both on experimental large-signal low-frequency I/V load-line characterization and a model-based description of the device capacitances. Such a technique allows to get the same information obtained through nonlinear measurement setups operating at microwave frequencies. Several simulated and experimental data are proposed, based on GaN technology, in order to prove the effectiveness of the methodology.
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ABSTRACT: A fully model-based nonlinear embedding device model including low- and high-frequency dispersion effects is implemented for the Angelov device model and successfully demonstrated for load modulation power-amplifier (PA) applications. Using this nonlinear embedding device model, any desired PA mode of operation at the current source plane can be projected to the external reference planes to synthesize the required multi-harmonic source and load terminations. A 2-D identification of the intrinsic PA operation modes is performed first at the current source reference planes. For intrinsic modes defined without lossy parasitics, most of the required source impedance terminations will exhibit a substantial negative resistance after projection to the external reference planes. These terminations can then be implemented by active harmonic injection at the input. It is verified experimentally for a 15-W GaN HEMT class-AB mode that, using the second harmonic injection synthesized by the embedding device model at the input, yields an improved drain efficiency of up to 5% in agreement with the simulation. A figure-of-merit is also introduced to evaluate the efficacy of the nonlinear embedding PA design methodology in achieving the targeted intrinsic mode operation given the model accuracy.IEEE Transactions on Microwave Theory and Techniques 09/2014; 62(9):1986-2002. DOI:10.1109/TMTT.2014.2333498 · 2.94 Impact Factor
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ABSTRACT: Continuing the historical view sketched by a companion contribution (cfr. A. Beyer), the major advances in microwave and millimeter-wave circuit design and device characterization will be outlined, as reflected and strengthened by the many valuable papers presented in the international workshop on “Integrated Nonlinear Microwave and Millimeter-Wave Circuits” (INMMiC). The contributions in the workshops from Rome (2004) to the last edition in Dublin (2012) will be briefly recalled.2014 International Workshop on Integrated Nonlinear Microwave and Millimetre-wave Circuits (INMMiC); 04/2014
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ABSTRACT: An innovative, recently introduced, methodology for microwave power amplifier design, is here extended to switching- mode Class-E amplifier operation. Such a technique is based on a complete and accurate electron device (ED) characterization, which is provided by both direct large-signal low-frequency I/V measurements, performed by means of a relatively simple low- cost setup, and a model-based description of nonlinear reactive effects related to ED capacitances. In order to verify the proposed design methodology, a Class-E power amplifier (PA) has been designed. Keywords-Design methodology; Integrated circuit design; Integrated circuit measurements; Microwave amplifiers; Power amplifiers; Waveform engineering I. INTRODUCTION Switching mode power amplifiers (PAs) are increasingly attracting microwave PA designers due to the excellent performance in terms of efficiency. Moreover, designers interest was surely encouraged by recent GaN technology that, due to the high breakdown voltage of GaN transistors, allows to overcome output power limitations related to switching classes of operation (e.g., Class-E (1)), that are mainly imposed by the maximum drain voltage achievable under nonlinear dynamic operation.