Linear Doherty Power Amplifier With an Enhanced Back-Off Efficiency Mode for Handset Applications (original) (raw)
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A Survey on RF and Microwave Doherty Power Amplifier for Mobile Handset Applications
Electronics
This survey addresses the cutting-edge load modulation microwave and radio frequency power amplifiers for next-generation wireless communication standards. The basic operational principle of the Doherty amplifier and its defective behavior that has been originated by transistor characteristics will be presented. Moreover, advance design architectures for enhancing the Doherty power amplifier’s performance in terms of higher efficiency and wider bandwidth characteristics, as well as the compact design techniques of Doherty amplifier that meets the requirements of legacy 5G handset applications, will be discussed.
Broadband HBT Doherty Power Amplifiers for Handset Applications
IEEE Transactions on Microwave Theory and Techniques, 2010
A Doherty power amplifier for IEEE 802.16e mobile worldwide interoperability for microwave access (m-WiMAX) is fully integrated on a 1 2 1 2 mm 2 die using a 2-m InGaP/ GaAs hetero-junction bipolar transistor (HBT) process. The direct input power dividing technique is employed on the chip. Broadband input and output matching techniques are used for broadband Doherty operation, and their effects are analyzed. A peaking amplifier 1.5 times larger than a carrier amplifier delivers high efficiency for m-WiMAX signal with a 9.6-dB crest factor and an 8.75-MHz bandwidth (BW). The PA with a supply voltage of 3.4 V has an EVM of 2.3% and a PAE of 31.5% at an output power of 24.75 dBm as well as an operating frequency of 2.6 GHz. A PAE over 30.3% and an output power of greater than 24.6 dBm with an EVM less than 3.15% and a gain variation of 0.2 dB are achieved across 2.5-2.7 GHz without any assisting linearization technique. After compensating AM-AM and AM-PM nonlinearity using a digital feedback predistortion algorithm, the PA exhibits a PAE of over 27% and an output power of over 23.6 dBm across 2.2-2.8 GHz while maintaining an EVM below 2.7%.
Ultra-Compact mm-Wave Monolithic IC Doherty Power Amplifier for Mobile Handsets
Electronics
This work develops a novel dynamic load modulation Power Amplifier (PA) circuity that can provide an optimum compromise between linearity and efficiency while covering multiple cellular frequency bands. Exploiting monolithic microwave integrated circuits (MMIC) technology, a fully integrated 1W Doherty PA architecture is proposed based on 0.1 μm AlGaAs/InGaAs Depletion-Mode (D-Mode) technology provided by the WIN Semiconductors foundry. The proposed wideband DPA incorporates the harmonic tuning Class-J mode of operation, which aims to engineer the voltage waveform via second harmonic capacitive load termination. Moreover, the applied post-matching technique not only reduces the impedance transformation ratio of the conventional DPA, but also restores its proper load modulation. The simulation results indicate that the monolithic drive load modulation PA at 4 V operation voltage delivers 44% PAE at the maximum output power of 30 dBm at the 1 dB compression point, and 34% power-added ...
Advanced Doherty power amplifier design for modern communication systems
2018
Mobile communication technologies are becoming increasingly sophisticated and have experienced rapid evolution over the last few decades, and this is especially true for the base station transmitter. In response to the ever increasing demand in communication traffic and data throughput, largely driven by video based social media platforms, both spectral and power efficient device and systems are needed to fulfil the requirements. In terms of energy consumption, the power amplifier is an important component, and although developing efficient technologies for handset equipment is important, it is the base station element of the communications system that poses the greater challenge, having to deal with many channels simultaneously, resulting in the need to linearly and efficiently amplify highly dynamic phase and amplitude modulated signals possessing very large peak-to-average power ratios, at high power levels. This unique set of challenges has led to continuous research to improve ...
A handset power amplifier with high efficiency at a low level using load-modulation technique
IEEE Transactions on Microwave Theory and Techniques, 2000
A new monolithic-microwave integrated-circuit power amplifier for cellular handsets has been implemented using the load-modulation concept of the Doherty amplifier, which has a high efficiency at a low power level. In order to get a compact module, the 4 transmission line for the load modulation is replaced by a passive high-pass -network, and the load-modulation circuit is also modified to function as a power-matching circuit of the main amplifier. The amplifier has two modes of operation, low-and high-power modes, controlled by a control voltage. At the high power mode, both the main and auxiliary amplifiers are operational and, at the low power mode, only the main amplifier generates output power enhancing the efficiency. For the code-division multiple-access environment, the amplifier at the low-power mode provides power-added efficiency PAE) of 39.8% and an adjacent channel power ratio (ACPR) less than 49.8 dBc at 23.1 dBm, and the high-power mode PAE of 37.9% and ACPR of 46.4 dBc at 28 dBm. The efficiency is improved by approximately 18.8% at out = 23 dBm by the load-modulation technique. For the advanced mobile phone system-mode operation, the amplifier delivers 26.1 dBm with PAE of 53% and 30.8 dBm with 48.7% at the low and high modes, respectively. Index Terms-Advanced mobile phone system (AMPS), cellular, code division multiple access (CDMA), Doherty amplifiers, handset, InGaP/GaAs HBT, load modulation, 4 transmission line, power amplifiers (PAs).
High Efficiency Power Amplifiers for Modern Mobile Communications: The Load-Modulation Approach
Electronics
Modern mobile communication signals require power amplifiers able to maintain very high efficiency in a wide range of output power levels, which is a major issue for classical power amplifier architectures. Following the load-modulation approach, efficiency enhancement is achieved by dynamically changing the amplifier load impedance as a function of the input power. In this paper, a review of the widely-adopted Doherty power amplifier and of the other load-modulation efficiency enhancement techniques is presented. The main theoretical aspects behind each method are introduced, and the most relevant practical implementations available in recent literature are reported and discussed.
2005 European Microwave Conference, 2005
We have proposed advanced design methods of Doherty amplifier for high efficiency base station power amplifiers with wide bandwidth. First, we develop Doherty amplifier with uneven power drive which is provided more input power to the peaking cell than the carrier cell for full power operation and appropriate load modulation. Second, we optimize the matching circuits of the carrier and peaking cells individually to enhance the linearity and efficiency. Third, we optimize the bias circuit to solve an asymmetric ACLR(Adjacent Channel Leakage Ratio) characteristics for wideband signals such as WCDMA 4FA. The proposed design methods are applied to implement Doherty amplifier using a MRF5P21180. For a 2.14 GHz WCDMA 4FA signal, the amplifier is optimized at 25 W average output power. The drain efficiency and ACLR measured at the power are 33 % and -41 dBc, which represent about 1.3 % and 3 dB improvements, respectively, compared to the Doherty amplifier with even power drive. Additionally, the PEP of the amplifier is about 180 W, while that of the comparable Doherty amplifier is about 165 W. The difference of ACLR with the bias circuit optimization between lower and upper ACLR is reduced below 2 dB at whole average output power range.
Design of power efficient power amplifier for B3G base stations
2010 9th International Symposium on Electronics and Telecommunications, 2010
Fourth generation systems require the use of both amplitude and phase modulation to efficiently utilize the available spectrum and to obtain high data rates, hence imposing stringent requirements on the power amplifier in terms of efficiency and linearity and requires the power amplifier to operate linearly and efficiently. The B3G base station transceiver Doherty power amplifier was designed to operate over the frequency range of 3.47GHz to 3.53GHz mobile WiMAX band using Freescale's N-Channel Enhancement-Mode Lateral MOSFET Transistor, MRF7S38010HR3; The performances of the Doherty amplifier are compared with that of the conventional Class AB amplifier. The results of 43 dBm output power and 66% power added efficiency are achieved.
Multi-band/multi-mode and efficient transmitter based on a Doherty Power Amplifier
2012
This paper presents the design of a high peak efficiency dual-band power amplifier (PA) and how it is adopted as basic cell to implement a high average efficiency Doherty PA (DPA), achieving a dual-band/multi-mode and efficient transmitter concurrently operating at 1.8 GHz and 2.4 GHz. From the dual-band PA, an average PAE of 25% has been experimentally obtained, when exited with concurrent 10MHz LTE and WiMAX signals. When using this PA as a basis for a dual band Doherty PA, the average PAE is improved (by 9 percentage units) to 34%. An adjacent channel leakage ratio (ACLR) lower than-46.5 dBc and-46.0 dBc has been fulfilled from PA and DPA, respectively, using a standard digital linearization technique.
Design of a Wideband Doherty Power Amplifier with High Efficiency for 5G Application
Electronics
This paper discusses the design of a wideband class AB-C Doherty power amplifier suitable for 5G applications. Theoretical analysis of the output matching network is presented, focusing on the impact of the non-ideally infinite output impedance of the auxiliary amplifier in back off, due to the device’s parasitic elements. By properly accounting for this effect, the designed output matching network was able to follow the desired impedance trajectories across the 2.8 GHz to 3.6 GHz range (fractional bandwidth = 25%), with a good trade-off between efficiency and bandwidth. The Doherty power amplifier was designed with two 10 W packaged GaN HEMTs. The measurement results showed that it provided 43 dBm to 44.2 dBm saturated output power and 8 dB to 13.5 dB linear power gain over the entire band. The achieved drain efficiency was between 62% and 76.5% at saturation and between 44% and 56% at 6 dB of output power back-off.