Linearised HBT MMIC power amplifier with partially RF coupled active bias circuit for W-CDMA portable terminals applications

A highly linear MMIC power amplifier for wideband code-division multiple-access (W-CDMA) portable terminals has been devised and implemented with a new integrated on-chip lineariser. The proposed lineariser, consisting of an InGaP/GaAs heterojunction bipolar transistor (HBT) active bias circuit partially coupled to RF input power together with a feedback capacitor, effectively improves gain compression with little insertion power loss and no additional die area. The optimised lineariser improves maximum output power (P1 dB) by 2 dB and adjacent channel leakage power ratio (ACLR) by 4 dB, and the implemented HBT MMIC power amplifier exhibits a P1 dB of 30 dBm, a power gain of 30 dB, a power added efficiency of 42% at the maximum output power under an operation voltage of 3.4 V, and an ACLR of -34 dBc at 27 dBm of output power.     

Linearised InGaP/GaAs HBT MMIC power amplifier with active biascircuit for W-CDMA application

A high linearity InGaP/GaAs heterojunction bipolar transistor (HBT) monolithic microwave integrated circuit (MMIC) power amplifier is demonstrated using a new structure for a bias circuit for wideband-code division multiple access (W-CDMA) application. A one shunt capacitor is added to a novel active bias circuit and acts as a lineariser improving input P_{1 dB} of 16 dB and phase distortion of 5.1° for the hybrid phase shift keying (HPSK) modulated signal at the 28 dBm output power; the lineariser showing no significant increase of signal loss and chip area. The two-stage HBT MMIC amplifier exhibits a power-added efficiency (PAE) of 37%, a linear power gain of 24.5 dB, and an output power of 28 dBm with an adjacent channel power ratio (ACPR) of -45 dBc, under a 3 V operation voltage     

SiGe MMIC power amplifier with on-chip lineariser for X-band applications

An X-band linear power amplifier with an on-chip lineariser is developed using a 0.25 mum SiGe HBT BiCMOS process. The proposed on-chip lineariser improves the 1 dB compression to as much as 3.4 dB with no additional DC power consumption. Under a 3.3 V DC power supply, the single-stage cascode amplifier shows a measured small-signal gain of 12.2 dB and output PI dB of 20.8 dBm, with power added efficiency of 27.4% at the operating frequency range 8.5-10.5 GHz.     

A Low Distortion and Low Dissipation Power Amplifier with Gate Bias Control Circuit for Digital/Analog Dual-Mode Cellular Phones

A power amplifier operating at 3.3 V. has been developed for CDMA/AMPS dual-mode cellular phones. It consists of linear GaAs power MESFET's, a new gate bias control circuit, and an output matching circuit which prevents the drain terminal of the second MESFET from generating the harmonics. The relationship between the intermodulation distortion and the spectral regrowth of the power amplifier has been investigated with gate bias by using the two-tone test method and the adjacent channel leakage power ratio (ACPR) method of CDMA signals. The dissipation power of the power amplifier with a gate bias control circuit is minimized to below 1000 mW in the range of the low power levels while satisfying the ACPR of less than ?26 dBc for CDMA mode. The ACPR of the power amplifier is measured to be ?33 dBc at a high output power of 26 dBm.     

改进负载调制的GaN Doherty功率放大器及其线性化

在分析传统Doherty负载调制的基础上,通过选取合适的峰值放大器负载阻抗和采用较高的偏置电压,增强了Doherty功率放大器的负载调制,使其适用于大范围（9dB）回退情况下的应用。为了验证分析的有效性,设计和实现了一个具有100MHz瞬时带宽的2.55GHz GaN Doherty功率放大器。测试结果表明：在工作带宽内饱和功率约为49.4dBm,平均峰值效率为64%,9dB回退时的平均效率约为40%。当使用5载波100MHz带宽LTE-advanced信号激励时,在平均输出功率为40.2dBm时效率可达40.3%,经过数字预失真校正过的邻道泄漏比（ACLR）低于-48dBc,达到较好的线性度。     

An X-band four-way combined GaN solid-state power amplifier

An X-band four-way combined GaN solid-state power amplifier module is fabricated based on a self-developed AlGaN/GaN HEMT with 2.5-mm gate width technology on SiC substrate. The module consists of an Al-GaN/GaN HEMT, Wilkinson power hybrids, a DC-bias circuit and microstrip matching circuits. For the stability of the amplifier module, special RC networks at the input and output, a resistor between the DC power supply and a transistor gate at the input and 3λ/4 Wilkinson power hybrids are used for the cancellation of low frequency self-oscillation and crosstalk of each amplifier. Under V_(ds)= 27 V, V_(gs) = -4.0 V, CW operating conditions at 8 GHz, the amplifier module exhibits a line gain of 5 dB with a power added efficiency of 17.9%, and an output power of 42.93 dBm; the power gain compression is 2 dB. For a four-way combined solid-state amplifier, the power combining efficiency is 67.5%. It is concluded that the reduction in combining efficiency results from the non-identical GaN HMET, the loss of the hybrid coupler and the circuit fabricating errors of each one-way amplifier.     

A Linear Power Amplifier Design Using an Analog Feedforward Method

We propose and describe the fabrication of a linear power amplifier (LPA) using a new analog feedforward method for the IMT‐2000 frequency band (2,110–2,170 MHz). The proposed analog feedforward circuit, which operates without a pilot tone or a microprocessor, is a small and simple structure. When the output power of the fabricated LPA is about 44 dBm for a two‐tone input signal in the IMT‐2000 frequency band, the magnitude of the intermodulation signals is below ?60 dBc and the power efficiency is about 7%. In comparison to the fabricated main amplifier, the magnitude of the third intermodulation signal decreases over 24 dB in the IMT‐2000 frequency band.     

基于GaN HEMT的高线性星载Doherty功率放大器设计北大核心CSCD

在射频通信链路中,功率放大器决定了发射通道的线性、效率等关键指标。卫星通信由于是电池供电,对功率放大器的工作效率要求比较高。文章基于GaN HEMT晶体管采用对称设计完成了一款高效率的Doherty功率放大器。测试结果表明:该Doherty功放的功率增益大于29 dB;1 dB压缩点功率(P_(1 dB))大于35 dBm;在35 dBm输出时,其功率附加效率(PAE)大于47.5%,三阶交调失真(IMD3)大于35 dBc;在功率回退3 dB时,其PAE大于37%,IMD3大于32 dBc。     

Analysis of a Fully Matched Saturated Doherty Amplifier With Excellent Efficiency

A saturated Doherty amplifier based on class-F amplifiers is analyzed in terms of its load modulation behavior, efficiency, and linearity. Simulations included the amplitude ratio and phase difference between the fundamental and third harmonic voltages, the current/voltage waveforms, load lines, and the third-order intermodulation amplitudes/phases of the carrier and peaking amplifiers. The saturated doherty power amplifier was implemented using two Eudyna EGN010MK GaN HEMTs with a 10-W peak envelope power. For a 2.14-GHz forward-fink wideband code-division multiple-access signal, the doherty amplifier delivers an excellent efficiency of 52.4% with an acceptable linearity of -28.3 dBc at an average output power of 36 dBm. Moreover, the amplifier can provide the high linearity performance of -50 dBc using the digital feedback predistortion technique.     

基于AlGaN/GaN HEMT的C波段混合集成功率合成放大器的设计

研制了一种基于AlGaN/GaN HEMT的功率合成技术的混合集成放大器电路.该电路包含4个10×120 μm的HEMT晶体管以及一个Wilkinson功率合成器和分配器.在偏置条件为VDS=40V,IDS=0.9A时,输出连续波饱和功率在5.4GHz达到41.4dBm,最大的PAE为32.54%,并且功率合成效率达到69%.     

Evaluation of multi-tone signal in the presence of the pre-distortion lineariser

In this article, analysis of a linearised travelling tube amplifier (TWT) using multi-tone signal under the digital modulation schemes is presented. The pre-distortion lineariser circuit based on the Schottky diodes is used to compensate for the nonlinear behaviour of the TWT amplifier in the noisy channel. The stability of the TWTA in combination with the lineariser has also been investigated through simulations. The 4-QAM and QPSK modulators are utilised and applied before linearised TWTA and capture results. The data passing through the linearised TWTA is analysed by using advanced design system (ADS). Constellation and eye diagrams are obtained from different modulation schemes and compared with each other in the same environment. Finally, the bit-error-rate (BER) performance of the system is evaluated using Monte Carlo estimation for three different values of input-back-off (IBO). It is shown that the performance is improved by applying the proposed signal pre-distortion lineariser.     

Bandpass delta-sigma class-S amplifier

A class-S amplifier with a bandpass delta-sigma modulated input is demonstrated using CMOS devices at 10 MHz. With a two-tone modulated input, third-order intermodulation products below -40 dBc were measured, with an output power of 26 dBm and a drain efficiency of 33%. This new amplifier topology demonstrates promising performance for simultaneously achieving high linearity and efficiency     

应用于WiFi6的新型高线性度功率放大器设计

针对WiFi 6的设备需求,设计了一款工作在5.15 GHz～5.85 GHz的高线性度砷化镓异质结双极型晶体管射频功率放大器。为了保证大信号和高温下功率管静态工作点的稳定性,采用了一种新型有源自适应偏置电路。对射频功率检测电路进行了设计和改进,有效降低了射频系统的功耗。针对各次谐波分量产生的影响,对输出匹配网络进行了优化。仿真结果表明：该射频功率放大器芯片小信号增益达到了32.6 dB;在中心频率5.5 GHz时1 dB压缩点功率为30.4 dBm,功率附加效率超过27.9%;输出功率为26 dBm时,三阶交调失真低于-40 dBc。实测数据表明：小信号增益大于31.4 dB;5.5 GHz时1 dB压缩点功率为29.06 dBm;输出功率为26 dBm时,三阶交调失真低于-30 dBc。当输出功率为20 dBm时,二次三次谐波抑制到-30 dBc和-45 dBc。     

采用90°分支电桥的C波段预失真线性化器

为了改善功率放大器的三阶交调失真,提出了一种基于90°分支线电桥的C波段预失真线性化器,使用肖特基二极管产生非线性信号。通过改变线性化器的偏置电压及电容,可调整线性化器的增益扩张和相位延迟特性,与功放级联后对功放的三阶交调失真有改善作用。将该线性化器应用到工作频率为7 GHz,饱和功率为20 dBm的放大器上,在输出功率回退5 dBm处对放大器的三阶交调有10 dBc的改善。     

A temperature-dependent nonlinear analysis of GaN/AlGaN HEMTs usingVolterra series

Gain and intermodulation distortion of an AlGaN/GaN device operating at RF have been analyzed using a general Volterra series representation. The circuit model to represent the GaN FET is obtained from a physics-based analysis. Theoretical current-voltage characteristics are in excellent agreement with the experimental data. For a 1 μm×500 μm Al_0.15Ga_0.85N/GaN FET, the calculated output power, power-added efficiency, and gain are 25 dBm, 13%, and 10.1 dB, respectively, at 15-dBm input power, and are in excellent agreement with experimental data. The output referred third-order intercept point (OIP₃) is 39.9 dBm at 350 K and 33 dBm at 650 K. These are in agreement with the simulated results from Cadence, which are 39.34 and 35.7 dBm, respectively. At 3 GHz, third-order intermodulation distortion IM₃ for 10-dBm output power is -72 dB at 300 K and -56 dB at 600 K. At 300 K, IM₃ is -66 dB at 5 GHz and -51 dB at 10 GHz. For the same frequencies, IM ₃ increases to -49.3 and -40 dB, respectively, at 600 K     

Highly Linear and Efficient Microwave GaN HEMT Doherty Amplifier for WCDMA

A highly linear and efficient GaN HEMT Doherty amplifier for wideband code division multiple access (WCDMA) repeaters is presented. For better performance, the adaptive gate bias control of the peaking amplifier using the power tracking circuit and the shunt capacitors is employed. The measured one‐carrier WCDMA results show an adjacent channel leakage ratio of ?43.2 dBc at ±2.5‐MHz offset with a power added efficiency of 40.1% at an average output power of 37 dBm, which is a 7.5 dB back‐off power from the saturated output power.     

A Novel Linearization Method of CMOS Drive Amplifier Using IMD Canceller

A novel linearization method for CMOS drive amplifier using intermodulation distortion (IMD) canceller is presented. The IMD cancellation method is composed of a cascode main amplifier and a common-source IMD canceller. The additional common-source amplifier generates IMD3 signals with 180deg phase difference against the IMD3 of the cascode main amplifier. The linear drive amplifier is designed and fabricated by CMOS 0.18 mum process. The output IP₃ of +13 dBm is achieved with the power gain of +11.6 dB, the output P_{1 dB} of + 5.5 dBm, and the power-added efficiency of 21%.     

一种S波段宽带GaN放大器的设计

氮化镓功率管的宽带隙、高击穿电场等特点,使其具有带宽宽,高效特性等优点。为了研究GaN功率放大器的特点,使用了AgilentADS等仿真软件,进行电路仿真设计,设计制作了一种s波段宽带GaN功率放大器。详述了电路仿真过程,并对设计的宽带GaN功率放大器进行测试,通过测试的实验数据表明,设计的宽带放大器在s波段宽带内可实现功率超过44dBm的功率输出,验证了GaN功率放大器具有宽带的特点。     

Analog IC-Achievable Lineariser for Power Amplifiers Based on Adaptive Feedforward

A compensation technique for the amplitude and phase imbalances of a feedforward lineariser using the LMS algorithm, implemented entirely in the analog domain, is presented. The lineariser is suited to RF power amplifiers, and maybe entirely developed with analog IC technologies. From simulated two-tone tests, the circuit leads to an intermodulation (IMD) reduction superior to 35 dB for a 64-QAM signal, being cheaper and competitive in performance with usual DSP-based adaptation circuits. Different implementations are evaluated, and the application of the circuit to RF power amplifiers in the DVB-T and in the LMDS frequency bands is considered.     

基于实频技术的超宽带GaN功率放大器研究

针对Lange耦合器在超宽带功率放大器中的应用,设计了一款基于实频技术的超宽带GaN功率放大器.匹配网络采用微带结构,应用微波CAD软件对所设计的电路进行仿真和优化,工作带宽为2～4 GHz,放大器增益大于26 dB,增益平坦度±0.3 dB,输出功率达到40 dBm,PAE大于25％.使用相对介电常数为3.38、厚度为0.508mm的介质基板实现该放大器,可广泛应用于通信领域.