TY - JOUR
T1 - Frequency Reconfigurable mm-Wave Power Amplifier With Active Impedance Synthesis in an Asymmetrical Non-Isolated Combiner
T2 - Analysis and Design
AU - Chappidi, Chandrakanth R.
AU - Sengupta, Kaushik
N1 - Funding Information:
This work was supported in part by the National Science Foundation and in part by the Office of Naval Research. This paper was approved by Associate Editor Kenichi Okada.
Publisher Copyright:
© 1966-2012 IEEE.
PY - 2017/8
Y1 - 2017/8
N2 - A frequency reconfigurable millimeter-wave (mm-wave) power amplifier (PA), which can be programmed to operate efficiently for a wide swathe of the spectrum, approaching an universal transmitter, can enable a wide range of novel applications in high-speed communication, sensing, and imaging. Classical techniques to allow large operating range either rely on broadband higher order output combining networks or tunable passives, both of which tradeoff directly with output power and efficiency. In this paper, we present an active impedance synthesis methodology that exploits the interaction of multiple unit PA cells in an asymmetrical non-isolated combiner to synthesize complex mm-wave impedances in a programmable fashion. This allows the interacting power cells to see their optimal load-pull impedances for high-efficiency frequency-reconfigurable operation in an efficient combiner network with no lossy variable passives. Compared to a symmetrical combiner, this enables the network to break the strong tradeoffs between output power, efficiency, and frequency reconfigurability, allowing it to achieve N times the Bode-Fano bound compared with an N-way symmetrical architecture. As a proof of concept, an integrated PA, which is in a 0.13- \mu \text{m} SiGe process, is demonstrated to achieve P-{{{\text {sat}}}} of 23.6 dBm at a power-added efficiency (PAE) of 27.7% at 55 GHz with a frequency reconfigurable P-{{\text {sat}},-1} sat 1 dB bandwidth of 25 GHz (40-65 GHz) and a PAE,-1 dB bandwidth of 20 GHz (40-60 GHz). Multi-Gbps data rates are demonstrated with non-constant envelope modulations across the frequencies 40-60 GHz.
AB - A frequency reconfigurable millimeter-wave (mm-wave) power amplifier (PA), which can be programmed to operate efficiently for a wide swathe of the spectrum, approaching an universal transmitter, can enable a wide range of novel applications in high-speed communication, sensing, and imaging. Classical techniques to allow large operating range either rely on broadband higher order output combining networks or tunable passives, both of which tradeoff directly with output power and efficiency. In this paper, we present an active impedance synthesis methodology that exploits the interaction of multiple unit PA cells in an asymmetrical non-isolated combiner to synthesize complex mm-wave impedances in a programmable fashion. This allows the interacting power cells to see their optimal load-pull impedances for high-efficiency frequency-reconfigurable operation in an efficient combiner network with no lossy variable passives. Compared to a symmetrical combiner, this enables the network to break the strong tradeoffs between output power, efficiency, and frequency reconfigurability, allowing it to achieve N times the Bode-Fano bound compared with an N-way symmetrical architecture. As a proof of concept, an integrated PA, which is in a 0.13- \mu \text{m} SiGe process, is demonstrated to achieve P-{{{\text {sat}}}} of 23.6 dBm at a power-added efficiency (PAE) of 27.7% at 55 GHz with a frequency reconfigurable P-{{\text {sat}},-1} sat 1 dB bandwidth of 25 GHz (40-65 GHz) and a PAE,-1 dB bandwidth of 20 GHz (40-60 GHz). Multi-Gbps data rates are demonstrated with non-constant envelope modulations across the frequencies 40-60 GHz.
KW - Bandwidth
KW - Bode-Fano
KW - SiGe
KW - broadband
KW - combiner
KW - load-pull
KW - loss
KW - millimeter-wave (mm-wave)
KW - multi-port
KW - networksynthesis
KW - power amplifier (PA)
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U2 - 10.1109/JSSC.2017.2686843
DO - 10.1109/JSSC.2017.2686843
M3 - Article
AN - SCOPUS:85021714454
SN - 0018-9200
VL - 52
SP - 1990
EP - 2008
JO - IEEE Journal of Solid-State Circuits
JF - IEEE Journal of Solid-State Circuits
IS - 8
M1 - 7948776
ER -