There is a growing interest in exploring antenna-electronic co-designs that leverage antennas (including their low-loss metal structures, design versatility, multi-feed driving capabilities) as a new design paradigm to radically advance mm-wave front-end performance. In particular, enhancing the peak/back-off transmitting efficiency is essential for future mm-wave wireless communications, such as 5G, which will predominantly use complex modulations with large peak-to-average-power ratio (PAPR) and extra power back-off (PBO) for linearity and reliability. Consequently, mm-wave transmitters often operate at deep PBO (9 to 12dB) with poor average efficiency. Although mm-wave Doherty/Outphasing PAs have been widely explored, there is limited success in high-order active load modulation for deep-PBO efficiency enhancement with high PA linearity, mainly due to the complexity and prohibitive loss of on-chip passive networks. On the other hand, most existing antenna-electronic radiators only follow basic Class-AB/B efficiency roll-off with rapidly degraded PBO efficiency [1,2]. Some use active load modulation on a single multi-feed antenna, whose simple structures support only 6dB PBO efficiency enhancement and limited PBO extension [3].
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Fei Wang,et al.
17.3 A 60GHz on-chip linear radiator with single-element 27.9dBm Psat and 33.1dBm peak EIRP using multifeed antenna for direct on-antenna power combining
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2017,
2017 IEEE International Solid-State Circuits Conference (ISSCC).
[2]
Patrick Reynaert,et al.
Transformer-Based Doherty Power Amplifiers for mm-Wave Applications in 40-nm CMOS
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2015,
IEEE Transactions on Microwave Theory and Techniques.
[3]
Hua Wang,et al.
A 62-to-68GHz linear 6Gb/s 64QAM CMOS doherty radiator with 27.5%/20.1% PAE at peak/6dB-back-off output power leveraging high-efficiency multi-feed antenna-based active load modulation
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2018,
2018 IEEE International Solid - State Circuits Conference - (ISSCC).
[4]
Ali Hajimiri,et al.
A 69-to-79GHz CMOS multiport PA/radiator with +35.7dBm CW EIRP and integrated PLL
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2018,
2018 IEEE International Solid - State Circuits Conference - (ISSCC).