Implementation of a current-mode class-S RF power amplifier with GaN HEMTs for LTE-Advanced

Ma, Rui; Wang, Zhancang; Yang, Xiaokun; Lanfranco, Sandro

doi:10.1109/wamicon.2012.6208440

Cited by 5 publications

(6 citation statements)

References 4 publications

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“…16). Next, the digital IF-RF converter mixes carrier frequency to RF according to (1). The resulted RF signal is a 3-level PWM, 32 divided phase in parallel.…”

Section: Block Descriptionmentioning

confidence: 99%

“…Here, a particularly important power coding block is necessary to quantize the modulated signal with varying envelope (like OFDM) and thus to generate high speed digital-RF pulse bits for SMPA. In recent years, the advancement of GaN HEMT transistor technologies (higher power density, f t , and lower switching loss) has made this architecture very attractive for digital base station applications [1]. However, the very low power coding efficiency (<30%) of the traditional power encoders (delta sigma modulator (DSM) [2], noise shaped pulse width modulator (PWM) [3], [4] and pulse position modulator (PPM) [5]) cause total TX efficiency degradation.…”

Section: Introductionmentioning

confidence: 99%

“…The generated PWM I and PWM Q with the minimized bit-resolution are digitally up-converted to RF using the 4-phase LO RF , see(1) RF PWM I · LO RFI PWM Q · LO RFQ…”

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confidence: 99%

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FPGA implemented multi-level IFPWM power coding for class-S PA in an all-digital GHz LTE transmitter

Zhu

Duan

et al. 2014

2014 IEEE International Wireless Symposium (IWS 2014)

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This work presents a new efficient multi-level intermediate frequency pulse width modulation (ML-IFPWM) power coding algorithm for switch-mode power amplifier. The merits of high power coding efficiency with distortion correction function are demonstrated by a FPGA implemented digital front end. Measurement results have shown power coding efficiency greater than 45%. To our knowledge, this is the firstly reported implemented discretetime domain 3-level power encoding approach with 5-MHz LTE signal at RF carrier frequency around 2 GHz. This can be used to generate multi-level digital pulse-train for advanced class-S PA in cellular digital base stations. Index Terms -Digital-RF transmitter, FPGA, multi-level encoder, power coding efficiency, pulse width modulator (PWM), microwave power amplifiers, switch-mode PA.

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“…16). Next, the digital IF-RF converter mixes carrier frequency to RF according to (1). The resulted RF signal is a 3-level PWM, 32 divided phase in parallel.…”

Section: Block Descriptionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

FPGA implemented multi-level IFPWM power coding for class-S PA in an all-digital GHz LTE transmitter

Zhu

Duan

et al. 2014

2014 IEEE International Wireless Symposium (IWS 2014)

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“…Several system-level solutions have been published, like a digital polar [1], digital out-phasing [2], and Cartesian direct digital topology [3]. As an alternative topology, [4]- [8] have introduced the concept of an all-digital Class-S TX. The basic concept is that using modulator, a fast 1-bit switching signal is generated conveying both phase and amplitude information.…”

Section: Introductionmentioning

confidence: 99%

An All-Digital Gigahertz Class-S Transmitter in a 65-nm CMOS

Zhao

Shen

Xue

et al. 2016

IEEE Trans. VLSI Syst.

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A 65-nm all-digital Class-S transmitter with an entire digital frontend (DFE) and a current-mode Class-D (CMCD) power amplifier (PA) is presented. To realize the high operation rate and performance of the DFE, which includes a 1-bit band-pass modulator, a mixer, and interpolation filters, approaches, such as time-interleaving algorithm and modified Manchester encoding, are adopted. The main blocks in the DFE are implemented using standard cells with electronic design automation tools for synthesis and place and route. A CMCD PA with an ON-chip transformer is designed and integrated. This Class-S transmitter exhibits a 40-MHz bandwidth at up to a 1.6 GHz output carrier frequency. Measurements with a 1-MHz channel-spacing π/4 quadrature phase shift keying signal show a power control range of −18.66 to −4.65 dBm, and the power consumption of the modulator core is 7 mW.

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“…To improve efficiency, many kinds of Doherty power amplifiers have been designed to achieve high efficiency in a wide dynamic range [9][10][11][12]. Furthermore, as one of the most promising semiconductor technique, GaN HEMT has been used for recent power amplifier designs, and it is an ideal choice in order to meet the requirement of wide bandwidth of LTE-Advanced system [13][14][15]. On the other hand, in order to improve the linearity of Doherty power amplifier, one of the possible and simplified techniques is Composite Right/Left-Handed Transmission Lines (CRLH-TL) for its character of suppressing the second harmonic of the carrier amplifier of the Doherty power amplifier.…”

Section: Introductionmentioning

confidence: 99%

Design of Linearity Improved Asymmetrical Gan Doherty Power Amplifier Using Composite Right/Left-Handed Transmission Lines

Feng¹,

Liu²,

Yu³

et al. 2013

PIER B

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Abstract-A highly efficient asymmetrical GaN Doherty power amplifier using traditional λ/4 transmission line and an asymmetrical GaN Doherty power amplifier (DPA) using composite right/lefthanded transmission lines (CRLH-TL) for linearity improvement are presented in this paper. The CRLH-TL is designed to suppress the second harmonic of the output of the carrier amplifier. This DPA using CRLH-TL is designed for 3.5 GHz LTE-Advanced Application with 100 MHz bandwidth and 37 dBm average output power, the carrier and peaking amplifiers are fabricated with the same 30 W GaN HEMT and unevenly driven in purpose of maintaining high efficiency at back-off power (BOP) region. At 9-dB and 6-dB BOP, the DE achieves 30% and 40.1%, respectively, and the adjacent channel power ratio (ACPR) are less than −37.1 dBc for 40 MHz 16 QAM signal at 37 dBm. In addition, the further linearization of the DPA is realized by using digital predistortion (DPD), the ACPRs are improved to −49.6 dBc for 40 MHz 16 QAM signal. The measured results show linearity improvement compared with the traditional DPA.

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Implementation of a current-mode class-S RF power amplifier with GaN HEMTs for LTE-Advanced

Cited by 5 publications

References 4 publications

FPGA implemented multi-level IFPWM power coding for class-S PA in an all-digital GHz LTE transmitter

FPGA implemented multi-level IFPWM power coding for class-S PA in an all-digital GHz LTE transmitter

An All-Digital Gigahertz Class-S Transmitter in a 65-nm CMOS

Design of Linearity Improved Asymmetrical Gan Doherty Power Amplifier Using Composite Right/Left-Handed Transmission Lines

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