C-band GaAs FET power amplifiers with 70-W output power and 50% PAE for satellite communication use

This paper describes a successfully developed high-power and high-efficiency C-band GaAs FET amplifier for satellite communication systems. To realize high efficiency in a high-power amplifier, an HFET well-designed for high-power applications is developed, and precise design for an amplifier is carried out. The HFET employed achieves reduction in a gate leakage current while maintaining a high maximum drain current. For precise design of an amplifier, large-signal FET model parameters are extracted using pulsed I-V and S-parameter measurements. Based on this model, second harmonic impedances as well as fundamental impedances are determined for obtaining high efficiency and input- and output-matching circuits which are assembled in a compact package are designed to achieve a high-efficiency internally matched amplifier. As a result, the amplifier delivers a high saturated output power of 70 W and a high power-added efficiency of 51%. These characteristics are the record power performance in C-band in terms of simultaneous achievement of high power and high efficiency. A low third order intermodulation distortion of -35 dBc is also obtained at a drain voltage of 10 V.     

A Wideband Power Amplifier MMIC Utilizing GaN on SiC HEMT Technology

The design and performance of a wideband power amplifier MMIC suitable for electronic warfare (EW) systems and other wide bandwidth applications is presented. The amplifier utilizes dual field plate 0.25- mum GaN on SiC device technology integrated into the three metal interconnect (3 MI) process flow. Experimental results for the MMIC at 30 V power supply operation demonstrate greater than 10 dB of small signal gain, 9 W to 15 W saturated output power and 20% to 38% peak power-added efficiency over a 1.5 GHz to 17 GHz bandwidth.     

Ultrahigh-efficiency power amplifier for space radar applications

This paper describes a broad-band switch mode power amplifier based on the indium phosphide (InP) double heterojunction bipolar transistor (DHBT) technology. The amplifier combines the alternative Class-E mode of operation with a harmonic termination technique that minimizes the insertion loss of matching circuitry to obtain ultrahigh-efficiency operation at X-band. For broad-band Class-E performance, the amplifiers output network employs a transmission line topology to achieve broad-band harmonic terminations while providing the optimal fundamental impedance to shape the output current and voltage waveforms of the device for maximum efficiency performance. As a result, 65% power-added efficiency (PAE) was achieved at 10 GHz. Over the frequency band of 9-11 GHz, the power amplifier achieved 49%-65% PAE, 18-22 dBm of output power, and 8-11 dB gain at 4 V supply. The reported power amplifier achieved what is believed to be the best PAE performance at 10 GHz and the widest bandwidth for a switch-mode design at X-band.     

High power-added efficiency MMIC amplifier for 2.4 GHz wirelesscommunications

This work describes the design and the measured performance of a high-efficiency monolithic microwave integrated circuit (MMIC) amplifier for wireless communications in the 2.4 GHz band. The monolithic technology employed in the circuit integration is based on standard 0.5-μm-gate-length MESFET. The design procedure is based on load-cycle graphic optimization of the transistor performance. On-wafer experimental characterization shows output power up to 24 dBm and excellent results of power-added efficiency up to 79% with 19.5 dBm output power at low drain bias voltage. The amplifier performance achieved and the circuit size, which is 1 mm², are suitable for use in the transmitter chains of wireless communication systems in the 2.4 GHz band     

GaAs FET power amplifier module with high efficiency

A high-efficiency GaAs FET power amplifier having a total efficiency of 70% and an output power of 2 W is realised in the 900 MHz band. A drain efficiency of 80% was achieved at a low operation voltage of 6 V. These high efficiencies were obtained by using the even-order harmonic tuning of an output matching circuit. Important parameters for achieving this efficiency are also clarified.     

High-Efficiency Broadband Parallel-Circuit Class E RF Power Amplifier With Reactance-Compensation Technique

Class E amplifier offers high efficiency approaching 100% for an ideal case. This paper introduces a first practical implementation of a novel broadband class E power amplifier design combining a parallel-circuit load network with a reactance compensation technique. The novel broadband parallel-circuit class E load network using reactance compensation technique has been discussed based on theory and its experimental verification. A proper guidelines method of designing a high-efficiency broadband class E power amplifier with an LDMOS transistor until the final prototype measurement and optimization will be discussed. In the measurement level, the drain efficiency of 74% at an operating power of 8 W and power flatness of 0.7 dB are achieved across a bandwidth of 136-174 MHz. The efficiency result is the highest result for VHF broadband frequency to date with a low supply voltage of 7.2 V. Simulations of the efficiency, output power, drain voltage waveform, and load angle (impedance) were verified by measurements and good agreements were obtained.     

A planar 4.5-GHz DC-DC power converter

In this paper, we present two DC-DC converters that operate at a microwave frequency. The first converter consists of a class-E switched-mode microwave amplifier, which performs the DC-AC conversion, and two half-wave diode rectifier outputs. The class-E MESFET amplifier has a minimum power-added efficiency of 86%, corresponding drain efficiency of 95%, and 120 mW of output power at 4.5 GHz. The diode rectifier has a maximum conversion efficiency of 98% and an overall efficiency of 83%. The second converter consists of a high-efficiency class-E oscillator and a diode rectifier. The class-E oscillator has a maximum efficiency of 57% and maximum output power of 725 mW. The DC-DC converter is planar and compact, with no magnetic components, and with a maximum overall DC-DC conversion efficiency of 64% for a DC input of 3 V, and the output voltage across a 87-Ω load of 2.15 V     

Analysis and design of continuous class-E power amplifier at sub-nominal condition

The continuous class-E power amplifier at sub-nominal condition is proposed in this paper. The class-E power amplifier at continuous mode means it can be high efficient on a series matching networks while at sub-nominal condition means it only requires the zero-voltage-switching condition. Comparing with the classical class-E power amplifier, the proposed design method releases two additional design freedoms, which increase the class-E power amplifier’s design flexibility. Also, the proposed continuous class-E power amplifier at sub-nominal condition can perform high efficiency over a broad bandwidth. The performance study of the continuous class-E power amplifier at sub-nominal condition is derived and the design procedure is summarised. The normalised switch voltage and current waveforms are investigated. Furthermore, the influences of different sub-nominal conditions on the power losses of the switch-on resistor and the output power capability are also discussed. A broadband continuous class-E power amplifier based on a Gallium Nitride (GaN) transistor is designed and testified to verify the proposed design methodology. The measurement results show, it can deliver 10–15 W output power with 64–73% power-added efficiency over 1.4–2.8 GHz.     

An efficient X-band 16-element spatial combiner of switched-mode power amplifiers

This paper describes the design, implementation, and characterization of a high-efficiency 10-GHz amplifier antenna array for spatial power combining. An average drain efficiency of 70% at 162 W effective isotropic radiated power, or about 1.5 W of transmitted power, is measured for an array of 16 amplifiers consisting of four four-element subarrays. The power-combining efficiency of the 16-element array is above 79%. The active device is a low-cost GaAs MESFET with a maximum available power in class A of 21 dBm. The single class-E power amplifier delivers 20.3 dBm with 67% drain efficiency and 58% power-added efficiency.     

AlInAs/GaInAs on InP HEMTs for low power supply voltage operation of high power-added efficiency microwave amplifiers

High power-added efficiency microwave power amplifier results are reported for AlInAs/GaInAs on InP HEMTs operated at relatively low power supply voltages (2.5-3 V). C-band power amplifiers are reported with power-added efficiencies as high as 67%, and output powers between 200 and 300 mW. This excellent performance at low power supply voltages is attributed to the high gain and low access resistances of the devices, which leads to a high drain efficiency despite the low power supply voltage.<>     

High-Efficiency Envelope-Tracking W-CDMA Base-Station Amplifier Using GaN HFETs

A high-efficiency wideband code-division multiple-access (W-CDMA) base-station amplifier is presented using high-performance GaN heterostructure field-effect transistors to achieve high gain and efficiency with good linearity. For high efficiency, class J/E operation was employed, which can attain up to 80% efficiency over a wide range of input powers and power supply voltages. For nonconstant envelope input, the average efficiency is further increased by employing the envelope-tracking architecture using a wide-bandwidth high-efficiency envelope amplifier. The linearity of overall system is enhanced by digital pre-distortion. The measured average power-added efficiency of the amplifier is as high as 50.7% for a W-CDMA modulated signal with peak-to-average power ratio of 7.67 dB at an average output power of 37.2 W and gain of 10.0 dB. We believe that this corresponds to the best efficiency performance among reported base-station power amplifiers for W-CDMA. The measured error vector magnitude is as low as 1.74% with adjacent channel leakage ratio of -51.0 dBc at an offset frequency of 5 MHz     

S波段高效GaN逆E类功率放大器

介绍一种高效逆E类功率放大器的设计方法,并选用GaN器件设计了工作于2.3GHz的逆E类功率放大器。当供电26V,输入功率26dBm时,放大器输出功率40.2dBm,工作效率76.1%,PAE为73.3%。提供了详尽的仿真与实测数据并对放大器性能进行分析。用数字预失真技术对逆E类功率放大器进行线性化校正并取得了良好的效果。     

基于ADS平台不对称Doherty功率放大器的仿真设计

为在高线性的前提下提高WCDMA基站系统中功率放大器的效率,仿真设计了一款工作于2.14 GHz频段不对称功率驱动的Doherty功率放大器。基于ADS平台,采用MRF6S21140H LDMOS晶体管,通过优化载波放大器和峰值放大器的栅极偏置电压改善三阶互调失真(IMD3),同时通过调节输入功率分配比例改善由于峰值放大器对载波放大器牵引不足导致的失配问题,从而改善不对称Doherty功率放大器的输出性能。仿真结果表明,当载波放大器的栅极偏置电压为2.84 V,峰值放大器的栅极偏置电压为0.85 V并且输入功率比例为1:2.3,输出功率为44 dBm时其功率附加效率(PAE)为24.21%,IMD3为-44.46 dBc,和传统AB类平衡功率放大器相比PAE提高了8.58%,IMD3改善了6.98 dBc。     

Watt-level Ka- and Q-band MMIC power amplifiers operating at lowvoltages

Ka- and Q-band watt-level monolithic power amplifiers (PAs) operating at a low drain bias of 3.6 V are presented in this paper. Design considerations for low-voltage operation have been carefully studied, with an emphasis on the effect of device models. The deficiency of conventional table-based models for low-voltage operation is identified. A new nonlinear device model, which combines the advantages of conventional analytical models and table-based models, has been developed to circumvent the numerical problems and, thus, to predict optimum load impedance accurately. The model was verified with load-pull measurements at 39 GHz. To implement a low-voltage 1-W monolithic-microwave integrated-circuit amplifier, careful circuit design has been performed using this model. A Q-band two-stage amplifier showed 1-W output power with a high power gain of 15 dB at 3.6-V drain bias. The peak power-added efficiency (PAE) was 28.5% and 1-dB compression power (P_{1 dB}) was 29.7 dBm. A Ka-band two-stage amplifier showed a P_{1 dB} of 30 dBm with 24.5-dB associated gain and 32.5% PAE. Under very low dc power conditions (P_dc<2 W, V_ds=3.4 V), the amplifiers showed 29-dBm output power and PAE close to 36%, demonstrating ultimate low-power operation capability. To the best of our knowledge, this is the first demonstration of watt-level PA's under 3.6-V operation at 26 and 40 GHz. Compared with the published data, this work also represents state-of-the-art performance in terms of power gain, efficiency, and chip size     

基于器件特性的改进高效率F类微带拓扑分析与实现

本文提出了一种新型的F类高效率功率放大器微带匹配拓扑。该拓扑简单紧凑且考虑了功率三极管输出端寄生效应,使得F类设计理论分析更贴合实际。基于提出的拓扑结构,采用商用10W GaN HEMT(Gallium-Nitrogen High Electron Mobility Transistor)进行了仿真与硬件实现。测试结果表明:当漏极偏置27V,工作频率2.995GHz时,实测输出功率为37.3dBm,功率附加效率为72.9%。在15~30V的偏置范围内,漏极调制效率达到68.9%以上。实测与仿真结果的吻合,很好的验证了拓扑的可行性。     

应用于4G-LTE无线通信系统的F类高PAE射频功率放大器

为了有效实现高谐波抑制并提高功率附加效率,提出了一种适用于4G-LTE无线通信系统的高效F类功率放大器。该功率放大器使用了低电压p-HEMT晶体管和小型微带抑制单元,能够在低射频输入功率下产生n次谐波抑制和较高的功率附加效率（power added efficiency,PAE）。采用谐波平衡法对提出的功率放大器进行了仿真分析,并对其进行了实际制造。通过实际测量对仿真结果进行了验证。测量结果显示,提出功率放大器的工作频率为1.8 GHz,带宽为100 MHz,平均PAE为76.9％,且具有2V的极低漏极电压。射频输入功率范围分别为0-12 dBm时,最大输出功率和增益分别为23.4和17.5 dBm。     

Highly efficient double-doped heterojunction FET's forbattery-operated portable power applications

Microwave power performance of double-doped AlGaAs-InGaAs-AlGaAs heterojunction field-effect transistors (HJFET's) operated at a drain bias of 3 V is described. The fabricated 1.0 μm gate-length HJFET exhibited a maximum drain current of 500 mA/mm, a transconductance of 300 mS/mm, and a gate-to-drain breakdown voltage of 10 V. Power performance for a 14 mm gate periphery device demonstrated a maximum output power of 1.7 W with a 66% power-added efficiency (PAE) at 900 MHz. When the device was tuned for a maximum PAE, it delivered a 71% PAE with an output power of 1.2 W. The results indicate that the developed HJFET has great potential for 3 V battery-operated portable power applications     

SiC MESFET微波功率器件的研制

利用本实验室生长的4H-SiC外延材料开展了SiC微波功率器件的研究.通过对欧姆接触和干法刻槽工艺的优化,研制出高性能的SiC MESFET.利用1mm栅宽SiC MESFET制成的微波功率放大器在2GHz 64V工作时,连续波输出功率达4.09W,功率增益为9.3dB,PAE为31.3%.文中还给出了SiC功率放大器在微波大信号工作时的稳定性的初步测试结果.     

SiC MESFET微波功率器件的研制

利用本实验室生长的4H-SiC外延材料开展了SiC微波功率器件的研究．通过对欧姆接触和干法刻槽工艺的优化,研制出高性能的SiCMESFET．利用1mm栅宽SiC MESFET制成的微波功率放大器在2GHz64V工作时,连续波输出功率达4．09W,功率增益为9．3dB,PAE为31．3％．文中还给出了SiC功率放大器在微波大信号工作时的稳定性的初步测试结果．     

高功率窄谱宽1 915 nm掺铥光纤激光器研究

开展了1 915 nm高功率、高效率、窄谱宽输出的掺铥光纤激光器（TDFL）研究。基于全光纤主振荡功率放大（MOPA）结构,采用40 W的793 nm半导体激光器泵浦纤芯直径25 m的双包层大模场面积（LMA）掺铥光纤,获得了最高功率12.1 W的1 915 nm窄谱宽连续种子激光输出。将8 W种子光注入掺铥光纤放大器,在793 nm激光泵浦功率为142.9 W时,获得了平均功率90 W的激光输出,其中心波长为1 915.051 nm,3 dB谱宽仅为94 pm,斜率效率为60.2%,光-光转换效率达63.0%。该系统在40 min运行考核时间内输出激光稳定性良好。