A fully-integrated digital-intensive polar Doherty transmitter

Shen, Yiyu; Mehrpoo, Mohammadreza; Hashemi, Mohsen; Polushkin, M.; Zhou, Lei; Acar, Mustafa; Leuken, René van; Alavi, Morteza S.; Vreede, Leo de

doi:10.1109/rfic.2017.7969051

Cited by 25 publications

(10 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, when dealing with modulated signals with high PAPRs, the control of the output power in an energy-efficient manner from a driver's perspective is needed. This can be achieved by using segmentation of the output stage [11], [12]. In low-power DTX implementations, this is done by putting many (scaled) unit cells in parallel, together with their embedded activation logic.…”

Section: A Segmentation Of the Rf Output Stagementioning

confidence: 99%

High-Power Digital Transmitters for Wireless Infrastructure Applications (A Feasibility Study)

Bootsman

Mul

Shen

et al. 2022

IEEE Trans. Microwave Theory Techn.

Self Cite

View full text Add to dashboard Cite

Fully digital transmitters (DTXs) have the potential of replacing analog-intensive transmitter (TX) line-ups in future massive multiple-input and multiple-output (mMIMO) systems since they hold the promise of higher system integration level and energy efficiency. DTX operation so far has been limited to low RF output powers. This article introduces a concept that enables high-power DTX operation. A DTX demonstrator targeting both high output power and high efficiency is realized as a proof of concept. It is based on a custom V T -shifted laterally-diffused MOS (LDMOS) technology, which is utilized to implement a segmented high-power output stage operated in class-BE. A lowvoltage high-speed 40-nm CMOS controller drives the individual output stage segments at gigahertz rates. Measurements show the promising results for the proposed high-power DTX concept and provide valuable lessons for future DTX implementations.

show abstract

Section: A Segmentation Of the Rf Output Stagementioning

confidence: 99%

High-Power Digital Transmitters for Wireless Infrastructure Applications (A Feasibility Study)

Bootsman

Mul

Shen

et al. 2022

IEEE Trans. Microwave Theory Techn.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Many techniques are developed to enhance the PA efficiency at PBO levels, such as envelope-tracking [1]- [4], Doherty [5]- [12], Class-G [13]- [15], and load modulation [16]- [21]. The supply modulator in envelope-tracking PA changes the supply voltage, which tracks the envelope of modulation signal to improve PBO efficiency.…”

Section: Introductionmentioning

confidence: 99%

A Quadrature Digital Power Amplifier With Hybrid Doherty and Impedance Boosting for Complex Domain Power Back-Off Efficiency Enhancement

Qian

Yang

Zhou

et al. 2021

IEEE J. Solid-State Circuits

View full text Add to dashboard Cite

A quadrature digital power amplifier (PA) with hybrid Doherty and impedance boosting (HDIB) technique is presented for deep power back-off (PBO) efficiency enhancement in the complex domain. Less power-combining ways and dc power supplies are required for proposed PA comparing to previously reported works with deep PBO efficiency enhancement. A reconfigurable matching network (RMN) based on a novel reconfigurable transformer is proposed with more freedom to achieve a flexible load impedance tuning range of the sub-PAs. The characteristics of the reconfigurable transformer based on tunable inductors are analyzed. Efficiency enhancement is achieved at 3-/6-/9-/12-/15-dB PBOs without any supply switching or PA short-switches. The PA is fabricated in 40-nm CMOS technology with a core size of 0.83 mm 2 . Operating at 2.3-3.4 GHz, it introduces 24.2-dBm peak P out with 38.5% peak drain efficiency (DE) at 2.8 GHz. It achieves 38.5%/29.6%/18.4% at 2.8 GHz and 34.7%/26.6%/17.8% DE at 3.3 GHz for 0-/6-/12-dB PBO, 39.3%/29.5%/14.9% at 2.8 GHz, and 35.3%/27.9%/15.9% DE at 3.3 GHz for 3-/9-/15-dB PBO, respectively. For 10-MHz 256-QAM modulation signal, it delivers 16.22-/15.50-dBm average P out with EVM of −32.3/−33.0 dB, average DE of 24.6%/22.7%, and ACLR of −33.20/−31.54 dBc at 2.8/3.3 GHz, respectively. For 20-MHz 64 QAM modulation signal, it exhibits 16.42-/15.52-dBm average P out with EVM of −29.1/−29.3 dB, average DE of 24.9%/22.78%, and ACLR of −30.78/−30.74 dBc at 2.8/3.3 GHz, respectively.

show abstract

“…Among different efficiency enhancement techniques such as envelope-tracking [19], [20] and Doherty [7], [21]- [31], Doherty PA [21] is still one of the most widely used efficiency enhancement techniques, because of its relatively simple and low-cost implementation. Using an off-chip matching network reduces the passives losses, thus increasing the efficiency especially at PBO compared to implementations with on-chip matching network [27]- [29].…”

Section: Introductionmentioning

confidence: 99%

“…Conventional TX design approaches are often based on using a nonlinear PA to achieve high efficiency and then linearize it by applying digital predistortion (DPD) techniques [7], [21]- [24], [26], [28], [29], [31]. Furthermore, as will be discussed in section IV, even with an ideal DPD, due to the highly nonlinear operation mode of class-E digital-PAs, it is not possible to achieve maximum spectral purity and minimum error-vector-magnitude (EVM) for a given number of bits with a conventional uniform digital-PA structure [32].…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, as will be discussed in section IV, even with an ideal DPD, due to the highly nonlinear operation mode of class-E digital-PAs, it is not possible to achieve maximum spectral purity and minimum error-vector-magnitude (EVM) for a given number of bits with a conventional uniform digital-PA structure [32]. The bandwidth of the digital AM signal is mostly limited by the sampling rate and not by analog blocks as in an analog-intensive polar TX [33], [34] thus, it can handle a higher signal bandwidth [9]- [12], [16]- [18], [29], [30]. In addition to high video bandwidth, high RF bandwidth is also of great importance.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A Highly Linear Wideband Polar Class-E CMOS Digital Doherty Power Amplifier

Hashemi

Zhou²,

Shen

et al. 2019

IEEE Trans. Microwave Theory Techn.

Self Cite

View full text Add to dashboard Cite

This paper presents the first application of a digital-intensive intrinsically linear digitally-controlled class-E technique in a Doherty configuration. By careful nonlinear segmentation and multiphase RF-clocking along with overdrive-voltage control and automatic duty-cycle correction, it is shown that even the nonlinearities related to Doherty operation can be fully handled by the underlying design such that digital predistorion DPD can be in principle omitted. The nonlinearity behaviour of the whole digital Doherty PA is analyzed and closed-form equations are given to predict the AM-AM and AM-PM curves. In addition, time/phase mismatch between the Peak and Main branches and the AM and PM signals are accurately compensated. In order to achieve maximum intrinsic linearity, two separate chips with the same architecture, but different design parameters, are fabricated as the Main and Peak amplifiers in 40nm bulk CMOS. To achieve a large RF bandwidth and high passive combiner efficiency, a differential low-loss, wideband Marchand balun-based Doherty power combiner, implemented using re-entrant coupled lines with independent 2 nd harmonic control is proposed, and together with the matching network is fabricated on a two-layer PCB. The measured peak / 6 dB power-back-off P OUT , drain efficiency / power-added efficiency at 2.4 GHz are 17.5 / 12.2 dBm, 57 / 52 % and 36 / 25 % with VDD Main / Peak = 0.6 / 0.7 V. Measured results without using DPD show-41 dBc ACPR and-36 dB EVM for a 16 MHz OFDM signal at 2.5GHz. By using DPD, the measured ACPR and EVM of a 16 / 32 MHz OFDM signals are-52 /-48 dBc and-50 /-48 dB respectively.

show abstract

A fully-integrated digital-intensive polar Doherty transmitter

Cited by 25 publications

References 6 publications

High-Power Digital Transmitters for Wireless Infrastructure Applications (A Feasibility Study)

High-Power Digital Transmitters for Wireless Infrastructure Applications (A Feasibility Study)

A Quadrature Digital Power Amplifier With Hybrid Doherty and Impedance Boosting for Complex Domain Power Back-Off Efficiency Enhancement

A Highly Linear Wideband Polar Class-E CMOS Digital Doherty Power Amplifier

Contact Info

Product

Resources

About