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Tham khảo tài liệu 'mobile and wireless communications network layer and circuit level design 2012 part 11', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Wireless Communications at 60 GHz A Single-Chip Solution on CMOS Technology 291 levels. The power added efficiency PAE of the PA is maximized when both the main and auxiliary amplifiers are equally powered. The maximum PAE for this PA is 3 . Frequency GHz Fig. 11. Measured small-signal performance of the 60-GHz Doherty power amplifier Fig. 12. Measured output power and gain of the 60-GHz Doherty power amplifier 292 Mobile and Wireless Communications Network layer and circuit level design Fig. 13. Measured current consumption and power added efficiency of the Doherty PA The International Technology Roadmap for Semiconductors ITRS 2007 has defined an FoM for the PA which links the output power P1dB with the gain PAE and frequency as a standard to compare different PAs. Table 2 provides a comparison of this PA with other published CMOS millimeter-wave PAs in terms of this FoM. Reference CMOS tech. Freq. ghZ Gain dB Psat dBm P1dB dBm PAE Architecture FoM Yao et al. 2007 90-nm 60 5.2 9.3 6.4 7.4 3-stage cascode 7.5 Suzuki et al. 2008 90-nm 60 8.0 10.6 8.2 - 3-stage common source - 90-nm 77 9.0 6.3 4.7 - - Chowdhury et al. 2008 90-nm 60 5.6 12.3 9.0 8.8 3-stage transformer 19.5 Wicks et al. 2008 130-nm 77 6.0 8.1 6.3 0.5 5-stage cascode 2.1 This work 130-nm 60 13.5 7.8 7.0 3.0 Doherty 15.2 Table 2. Performance comparison of the PA in this work and published millimetre-wave PAs on CMOS technology 6. Mixer The down-conversion mixer in the receiver is used to translate the input signal from RF to an intermediate frequency IF for processing by baseband circuits. An important consideration in homodyne receiver structures is the LO-to-RF isolation of the mixer. LO self-mixing Lee 2004 occurs when the LO signal which is at the same frequency as the RF signal leaks to the input of the mixer and then mixes with itself produces a time varying DC offset which significantly degrades the receiver s performance especially in OFDM systems. In the literature few results have been .
