Radio frequency multilevel switching mode power amplifiers with pulse-position and pulse-width modulation for efficient power amplification of broadband mobile communication signals
Final Report Abstract
Advances in mobile communications are leading to an increased number of carrier frequencies being used, larger signal bandwidths and higher-order modulation schemes, which increases the complexity of transmitters. In addition, more different frequency bands are being used, whereby high linearity and efficiency are required. Digital power amplifiers are a possible transmitter concept to meet these requirements. Compared to conventional analog implementations with class-A or class-B amplifiers, high flexibility with support for multiple frequency bands can be achieved. Furthermore, it is possible to integrate these power amplifiers monolithically with the digital baseband signal processor (BB-DSP) or complete digital systems. The focus of this project was therefore the implementation of a multi-level current mode switching mode power amplifier (ML-CM-SMPA), which can be used as an output stage for a fully digital RF transmitter. The phase information is encoded in the pulse position and the amplitude in the pulse width of the output signal of a high-frequency pulse width and position modulator (PWPM). The smallest pulse width is limited by the shortest pulse that can be amplified by the ML-CM-SMPA, which limits the dynamic range. In order to achieve a high dynamic range, the modulation of the pulse width is extended by switched discrete current levels, implemented by a switchable conductance of the ML-CM-SMPA switches. In this project, a carrier frequency range from 2 GHz to 6 GHz was demonstrated in an advanced FD-SOI CMOS technology, with a maximum output power of 22.5 dBm and maximum drain efficiency and system efficiency of 35.7% and 33.1%, respectively. For a 40 MBd 64-QAM signal at a carrier frequency of 3.6 GHz, an EVM of -30.9 dB was achieved. Compared to other CMOS power amplifiers in switching mode that support similar carrier frequencies, the highest carrier frequency range was achieved with the highest measured signal bandwidth of 1 GHz, demonstrated with 1 GBd QPSK signals.
Publications
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Real-Time Processing and Delta-Sigma Modulation on FPGA for Switching Mode RF Amplifiers, 2022 14th German Microwave Conference (GeMiC), Ulm, Germany
J. Tonn, T. Veigel, M. Wittlinger, M. Grözing & M. Berroth
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Switching Mode Power Amplifier Concept Combining Pulse-Width, Pulse-Position and Conductance Modulation, 2022 Kleinheubach Conference, Miltenberg, Germany
M. Wittlinger, M. Grözing & M. Berroth
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Switching Mode Power Amplifier for Fully Digital RF Transmitter at 3.6 GHz in 22 nm FD-SOI CMOS. 2023 18th Conference on Ph.D Research in Microelectronics and Electronics (PRIME), 5-8. IEEE.
Wittlinger, Manuel; Grözing, Markus & Berroth, Manfred
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A Frequency-Agile Digital-to-RF Power Amplifier in 22 nm FD-SOI CMOS Technology. 2024 19th European Microwave Integrated Circuits Conference (EuMIC), 74-77. IEEE.
Wittlinger, Manuel; Grözing, Markus; Berroth, Manfred & Rademacher, Georg
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Glitch-freier, jitterarmer Amplituden- und Phasenschalter für digitale RF-Pulsmodulation, Analog Workshop 2025, Berlin, Germany
Manuel Wittlinger, Jakob Finkbeiner, Raphael Nägele, Markus Grözing, Manfred Berroth & Georg Rademacher
