线性Doherty功放的优化设计

设计了一个高效率、高线性度的射频Doherty GSM基站功放。利用Doherty功放的载波放大器与峰值放大器之间的互调对消技术使Doherty功放的三阶互调干扰(IMD3)改善了11dBc;并通过相位补偿延迟线的前置处理进一步提高了功放的效率,使其效率比常用的平衡补偿线方案提高了4%左右。文中利用两个MRF9060功放管制作了一个GSM频段Doherty功放,其实测1dB压缩点功率(P1dB)达到了130W;双音测试表明:经过4.5dB的回退后三阶互调失真(IMD3)优于-35dBc,此时功率附加效率(PAE)高达47.3%;WCDMA 3GPP的测试结果表明:经过6dB回退后,其5MHz偏移量的邻道功率比(ACPR)优于-40.5dBc,PAE为43.5%,比AB类平衡功放的效率提高了17.8%。结果表明:该设计方案较好地解决了射频功放功率与效率之间的矛盾,适用于射频功放的设计。     

一种电调Doherty功率放大器

提出了一种全新的电调Doherty移动基站功率放大器。该Doherty放大器的载波放大器和峰值放大器的驱动功率分配比及输出合成相位实现了电可调,从而保证了Doherty功率放大器的最佳驱动功率分配比,以及最佳的输出合成相位,同时结合内部线性化技术以实现Doherty功率放大器的最优性能。为保证功率放大器性能的稳定,设计了一种用于Doherty功率放大器的恒静态偏置电路,在-25℃～+50℃的高低温实验中使放大器偏置电流的波动小于5%。功放的工作频率为870～890MHz,增益大于58dB。在CDMA2000信号测试下,输出功率为50.06dBm时,其ACLR(邻道泄漏功率比)小于-47.5dBc,整机效率达42.3%(含驱动级)。     

A broadband Doherty power amplifier with harmonic suppression

In this paper, the design and implementation of the broadband, Doherty power amplifier (DPA) with 2nd and 3rd harmonics suppression, with theoretical analysis is presented. In the proposed structure a novel harmonic suppressed Wilkinson power divider used in DPA, which results in harmonic suppression with high level of attenuation. Moreover the proposed DPA has major advantages in terms of the linearity and works on a wideband frequency range (2.1–2.7 GHz) with minimum 40% drain efficiency (DE). The linearity of the proposed DPA is increased extremely, which significant improvement (7 dBm) is achieved from the main amplifier. In the proposed DPA, the main and the auxiliary amplifiers are implemented using Class-AB and Class-C topology respectively with equal MRF6S27015N MOTOROLA transistors in LDMOS technology.     

一种基于阻抗缓冲匹配技术的高效率Doherty放大器

为了在功率回退时满足功率放大器对高效率的要求,提出了一种采用阻抗缓冲匹配技术的Doherty功率放大器。通过负载牵引仿真,得到功放管的最佳基波和谐波负载阻抗。在此基础上,采用一种谐波控制阻抗匹配网络设计方法来设计主/辅路放大器的输出匹配网络,实现了高回退效率。为了验证该方法的有效性,设计并实现了一个1.635 GHz高效率Doherty功率放大器。测试结果表明,该放大器的饱和功率大于44 dBm,峰值效率为75%,6 dB功率回退时的效率为70%。该方法能有效提高Doherty功率放大器的回退效率。     

A broadband high-efficiency Doherty power amplifier using symmetrical devices

This paper proposes a method for broadband and high-efficiency amplification of Doherty power amplifier (DPA) using symmetric devices.In order to achieve the perfect load modulation,the carrier amplifier output circuit total power length is designed to odd multiple of 90°,and the peak amplifier output total power length is designed to even multiple of 180°.The proposed method is demonstrated by designing a broadband high-efficiency DPA using identical 10-W packaged GaN HEMT devices.Measurement results show that over 51％ drain efficiency is achieved at 6-dB back-offpower,over the frequency band of 1.9-2.4 GHz.     

基于功放管最优负载阻抗的Doherty功率放大器效率提升方法

本文给出了一种提高Doherty功率放大器（DPA）效率的方法．为减轻非理想负载调制和膝点电压效应引起的DPA效率下降,首先分析得出了载波和峰值功放管负载阻抗应满足的要求,推导出了与载波放大器负载阻抗相关的等驻波比圆,并使用该圆得到了载波功放管的最优负载阻抗,以提高DPA的效率．根据所提方法设计并实现了一个工作在2．35GHz的非对称DPA．单音信号测试时,该放大器的饱和功率为49．3dBm,在峰值和8dB回退功率下其漏极效率分别高于68％和55％．五载波100MHz LTE-advanced信号激励下,输出功率40．5dBm时该放大器的平均效率为50．5％,其校正后的邻道泄露比（ACLR）低于－47．5dBc．实验结果表明,本文设计的非对称Doherty放大器具有较高的平均效率和良好的线性度性能,验证了所提方法的有效性．     

基于特定相移匹配的连续类双频Doherty放大器

为了实现Doherty功率放大器在双频模式下的宽带高效工作,设计了一种基于特定相移匹配的连续类双频Doherty放大器。利用相移周期重复性原理,通过确定两个目标频段上所需要的特定相移,结合连续类放大器技术,对匹配网络进行设计,解决了传统双频Doherty放大器带宽受限的问题。设计和实现了一个2.2~2.7 GHz和3.1~3.4 GHz的双频Doherty放大器。测试结果表明,该功率放大器两个频段的饱和效率分别为64.1%~68%和60.1%~66.3%,6 dB回退效率分别达到了45.2%~52.1%和44.1%~48.5%,能满足未来移动通信系统多频段同时工作的需求。     

基于GaAs HBT工艺的高增益宽带Doherty功率放大器设计

在传统Doherty功率放大器的基础上,采用砷化镓(GaAs)异质结双极晶体管(HBT)工艺,设计了一款可应用于5G通信N79频段(4.4~5 GHz)的高回退效率MMIC Doherty功率放大器(DPA)。通过在Doherty电路中采用共射-共基结构,并在共射-共基结构中加入共基极接地电容,大幅提升了DPA的增益和输出功率。使用集总元件参与匹配,减小了芯片的面积。仿真结果表明,在目标频段内,增益大于28 dB,饱和输出功率约为38 dBm,饱和附加效率(PAE)为63%,7 dB回退处的效率达到43%。     

A highly extended high-efficiency range Doherty power amplifier for high PAPR communication signals

In this paper, design, simulation and fabrication of a new highly extended high-efficiency range Doherty power amplifier (DPA) for high peak to average power ratio (PAPR) communication signals were presented with a main and only a single auxiliary amplifier. In order to extend the output high-efficiency range, it employed non-equal cells as main and auxiliary amplifiers in the complex combining load (CCL) methodology. As a new method, a new design parameter (\(\gamma\)) was added to the conventional complex combining load method. The effect of the new added design parameter on extension of output back-off (OBO) were analyzed and formulated. Also, to verify the proposed methodology, a DPA with 12 dB of OBO was designed, simulated and fabricated for WCDMA applications. Large signal continuous wave measurement results show the power gain of 11 dB with the drain efficiency of 53% at 12 dB of OBO. Two-tone test exhibits the third-order intermodulation distortion lower than ??34 dBc. Modulated wave simulations show over 51% of average drain efficiency and lower than ??31 dBc of adjacent channel leakage power ratio at output power level of 31.5 dBm.     

High-Power Amplifier Linearization Using the Doherty Amplifier as a Predistortion Circuit

This paper presents the application of a Doherty power amplifier (DPA) as a predistortion circuit for the linearization of high PA. When the DPA is employed as the driver amplifier, its nonlinearity is used as predistorted components to cancel the strong nonlinearity of the main amplifier. To verify the proposed method, the DPA is implemented with two 30-W silicon metal–oxide semiconductor field-effect transistors and tested with a 180-W main amplifier at a wideband code-division multiple access (WCDMA) band of 2.14 GHz. For a two-tone signal with 2-MHz tone spacing and a one-carrier WCDMA signal, the significant cancellation of the third- and fifth-order intermodulation (IM3 and IM5) components and a superior adjacent channel leakage ratio improvement are achieved.      

基于双向牵引与谐波抑制的Doherty功率放大器设计

为了提高功率放大器(Power Amplifier,PA)的效率,提出一种基于双向牵引与谐波抑制的对称式Doherty功率放大器(Symmetrical Doherty Power Amplifier,SDPA)结构。该结构在经典DPA 的基础上,首先利用多谐波双向牵引技术获得功放的实际最佳阻抗,然后对主辅功放的二、三次谐波进行抑制,降低了漏极电压电流的重合,最后通过添加补偿线调节主辅功放的功率分配,使得功放整体获得最大的效率。为了验证上述谐波抑制理论与双向牵引技术的正确性,采用GaN 器件设计了一款应用在4G 基站的SDPA。测试结果显示:SDPA 在2.6 GHz 处的小信号增益为12.6 dB,2.5-2.7 GHz 频段内的增益平坦度为±0.75 dB,频带内的S11小于-11.9 dB,在三载波测试时经过数字预失真(Digital Pre-Distortion,DPD)系统纠正后的相邻信道泄漏比(Adjacent Channel Leakage Rate,ACLR)约为-45 dBc,SDPA 在峰值功率点附近的功率附加效率(Power Added Efficiency,PAE)接近60%,在回退点处的PAE约为48%。实验结果验证了该设计方案的可行性。     

改进型宽带Doherty功率放大器的设计

根据Doherty技术,设计了一款改进型宽频带功率放大器。在设计过程中,分析了λ/4线对Doherty功率放大器(DPA)的影响。通过对阻抗比的研究,在理论上延拓了功放的带宽。此外,应用不对称功率输入结构来克服阻抗比变化所带来的非理想调制效应。为了证明文中的理论分析,采用飞思卡尔公司的LDMOSFET功放管MRF6S20010,最终设计实现了一款工作于1 900～2 200MHz的宽频带Doherty功率放大器。测试结果显示,改进型宽带功放相对于传统Doherty功率放大器有很大的优势,可用于无线通信领域。     

A 25 dBm Digitally Modulated CMOS Power Amplifier for WCDMA/EDGE/OFDM With Adaptive Digital Predistortion and Efficient Power Control

A digitally modulated power amplifier (DPA) in 1.2 V 0.13$ muhbox{m}$ SOI CMOS is presented, to be used as a building block in multi-standard, multi-band polar transmitters. It performs direct amplitude modulation of an input RF carrier by digitally controlling an array of 127 unary-weighted and three binary-weighted elementary gain cells. The DPA is based on a novel two-stage topology, which allows seamless operation from 800 MHz through 2$~$ GHz, with a full-power efficiency larger than 40% and a 25.2 dBm maximum envelope power.      

Unequal-Cells-Based GaN HEMT Doherty Amplifier With an Extended Efficiency Range

This letter reports an extended GaN HEMT Doherty power amplifier (DPA). For high efficiency over a wide output power range, the DPA is designed using two cells with unequal saturation power $(P_{rm sat})$. A cell with lower $P_{rm sat}$ is used as the carrier cell. For experimental validations, the carrier and peaking cells are designed and implemented with 25 W GaN HEMTs at wide-band code division multiple access (WCDMA) of 2.14 GHz, and then show the $P_{rm sat}$ of 41.3 dBm and 43.6 dBm, respectively. For the proposed DPA, the single-tone results show the power-added efficiency (PAE) of 50% at an output power of 37.3 dBm (9 dB back-off power from $P_{rm sat}$). For a one-carrier WCDMA signal, the PAE of 47.9% with an adjacent channel leakage ratio of ${-}$35.8 dBc is obtained at 37.3 dBm, which is 7.9% improvement compared to the conventional DPA. The PAE of 40% is maintained over an 11.4 dB back-off power.      

Highly Linear Power Tracking Doherty Amplifierfor WCDMA Repeater Applications

This letter presents a highly linear power tracking Doherty power amplifier (DPA) for wide-band code division multiple access (WCDMA) repeater system. To achieve maximum linearity without extra linearization circuits, the drain bias voltages of the carrier and peaking amplifiers as well as the gate bias voltage of the peaking amplifier are adaptively controlled using the power tracking method according to average power level of the input signal. For experimental verification, a two-way DPA has been implemented at the WCDMA band of 2.11~2.17 GHz and tested using one-tone, two-tone, and four-carrier WCDMA signals. Two-tone and WCDMA test results show the notable cancellation of the IM3 and IM5 components and the significant improvement in adjacent channel leakage ratio over a wide range of output power levels.     

逆F类高效氮化镓Doherty射频功率放大器设计*

逆F 类功放在接近饱和区工作时效率很高,将其与Doherty 功放结构相结合,可以实现一种在大功率回退的情况下仍然具有很高效率的射频功率放大器。本文设计了一款基于GaN HEMT 晶体管的高效率的逆F 类Doherty 功率放大器,工作频带为910MHz-950MHz。单音信号测试结果显示,在930MHz 处,功放回退7.5dB 后漏极效率仍高达64.2%。使用3 载波WCDMA信号作为测试信号,利用数字预失真技术进行线性化后,功放输出信号的上下边带邻信道功率比(ACPR)分别为-35.39dBc 和-35.9dBc。     

Transmission of optical communication signals by distributed parametric amplification

For the first time, to the authors' knowledge, distributed parametric amplification (DPA), i.e., the use of a transmission fiber itself for parametric amplification of communication signals is proposed and demonstrated. To account for the inevitable fiber loss, solutions were derived for the distributed amplifier, with either one or two pumps: They are obtained in terms of confluent hypergeometric functions. Low-penalty DPA of a 10-Gb/s nonreturn-to-zero (NRZ) signal over a 75-km dispersion-shifted fiber (DSF), is demonstrated by using only 66.5 mW of pump power. Three adjacent channels have been simultaneously transmitted, with little penalty due to nonlinear crosstalk. It is experimentally verified that DPA requires less pump power than distributed Raman amplification (DRA), for similar power penalties.     

有限容值隔直电容逆E类功放的分析与设计

提出了一种高效率逆E类功率放大器的设计方法--"有限容值隔直电容设计法",不仅确保放大器保持高工作效率,而且使其具有更低的漏极峰值电压、更大的功率输出能力、更高的上限工作频率及上限输出功率.本文制作了工作于155MHz,输出功率40.07dBm,工作效率83.87%,PAE82.57%的实际电路,实测结果与理论仿真结果基本一致,验证了理论分析的准确性.     

基于GaN 的3. 4~ 3. 6 GHz 高增益Doherty 功率放大器

基于两级功率放大器架构,设计了一款平均输出功率为37 dBm(5 W)的高增益Doherty 功率放大器。 该器件通过增加前级驱动功率放大器提高Doherty 功率放大器的增益,采用反向Doherty 功率放大器架构,将λ/4 波 长传输线放置在辅助功放后端,相位补偿线放置在主功放前端,并使主功放输出匹配网络采用双阻抗匹配技术实现 阻抗变换,如此可扩宽功率放大器的工作带宽。连续波测试结果显示:3. 4~3. 6 GHz 工作频段内,饱和输出功率在 44. 5 dBm 以上,功率饱和工作点PAE 在43. 9%以上;在平均输出功率(37 dBm,5 W)工作点,回退量大于7. 5 dB,功 率附加效率PAE 为36. 8%以上,功率增益在31 dB 以上。     

一种高效率逆F类Doherty射频功率放大器

为了进一步提高射频功放的输出能力,基于GaN HEMT功率器件,采用平衡式结构设计了一款工作频率为3.3 GHz 3.6 GHz的高效率逆F类Doherty结构射频功放。参照功放管的寄生参数等效电路网络,为获得逆F类功放理想的开关特性,设计了具有寄生参数补偿作用的谐波控制网络来抑制功放输出端的二次、三次谐波,同时结合Doherty功放结构特点,使其在6 dB功率回退的情况下仍具有较高的输出效率。仿真后,可得到其在3.3 GHz^3.6 GHz工作频带内的输出功率在40.4 dBm^41.8 dBm内,PAE为66%~77%,最大DE达到82.6%,功率回退6 dB处,功放的DE仍在69%左右,增益平坦度约为±1.5 dB。