基于ANSYS的射频功率放大器热特性研究

论文首先仿真设计了一款射频功率放大器,接着构建了该射频功率放大器热特性分析模型,并采用有限元方法分析了该射频功率放大器热特性,然后研究了增加过孔以及不同覆铜层厚度、环境温度、耗散功率四种情况对射频功率放大器的温度、热应力和热形变的影响,最后基于上述分析结论加工制作并测试了该款射频功率放大器.在3.3GHz~3.6GHz范围内其输出功率不低于39.2dBm,增益不低于12dB,功率附加效率为62.6%~69%;在环境温度为21℃下,运用红外温度扫描仪进行测试,该款射频功率放大器最高温度达到90.0℃,测试结果与仿真分析结果相近.论文的研究为未来射频功率放大器的设计及制作提供了重要指导.     

UHF宽带大功率放大器模块

报道了自行设计并研制成功的UHF宽带大功率放大器模块,该模块在1.35～1.85 GHz频带内增益高于44 dB,输出功率大于10 W,增益平坦度≤± 0.7 dB.同时对射频功率放大器的稳定性进行了分析与讨论,提出了提高射频功率放大器稳定性的方法,即要设法排除带外不稳定因素以及设计合理的偏置网络,这对射频功率放大器的稳定性有明显的改善.     

VHF跳频通信系统功率放大器的研制

设计了一种用于跳频通信系统的射频功率放大器.该放大器具有较高的线性度,同时又能实现高功率的稳定输出,低功率输出大于0.25 W,中功率输出大于4.5 W,滤波器衰减损耗小于2 dB,谐波抑制大于48 dB.介绍了VHF跳频发射机系统,包括逻辑电平转换单元、调制环单元、射频环单元、频率合成器单元和功放单元;着重对射频功率放大器的性能进行了分析,指出了提高功放线性度的特殊方法;给出了射频功率放大器的硬件电路设计过程.最后,对射频功率放大器进行测试,结果表明,其性能指标完全达到系统设计要求,并有所提高,而且具有较强的实用性.     

高线性度CMOS射频AB类功率放大器设计

CMOS射频AB类功率放大器广泛应用于单片集成无线芯片内.采用恒定最大电流的方法对其效率进行分析,采用归一化输入电压的方法对其线性度进行分析.利用AB类功率放大器系统增益的非线性与CMOS跨导非线性相互补偿,提高了CMOS射频AB类放大器的线性度.基于TSMC 0.18μm CMOS混合信号工艺,设计了一款两级射频AB类功率放大器.该射频功率放大器差动输入,单端输出,工作频段为804~940MHz,工作电压为3V.仿真指标为:增益为11dB,输出1dB压缩点为17.2dBm,OIP3为18.2dBm,附加效率为37%.     

VHF跳频通信系统功率放大器的研制

设计了一种用于跳频通信系统的射频功率放大器。该放大器具有较高的线性度,同时又能实现高功率的稳定输出,低功率输出大于0．25W,中功率输出大于4．5W,滤波器衰减损耗小于2dB,谐波抑制大于48dB。介绍了VHF跳频发射机系统。包括逻辑电平转换单元、调制环单元、射频环单元、频率合成器单元和功放单元;着重对射频功率放大器的性能进行了分析,指出了提高功放线性度的特殊方法;给出了射频功率放大器的硬件电路设计过程。最后,对射频功率放大器进行测试,结果表明,其性能指标完全达到系统设计要求,并有所提高,而且具有较强的实用性。     

用于IEEE 802.11 b/g/n WLAN的高线性度功率放大器

基于2μm的InGaP/GaAs异质结双极晶体管(HBT)工艺设计了一种可应用于IEEE802.11 b/g/n无线局域网(WLAN)的高线性度射频功率放大器.为了提高射频功率放大器的线性度,采用了负反馈镜像电路提供直流工作点,设计了良好的输入、输出和级间匹配电路来提高射频功率放大器的线性输出功率.流片结果表明,在工作电压为3.3V时,射频功率放大器的1 dB线性压缩输出功率(P1dB)可达27 dBm,当误差向量幅度(EVM)为3％时,2.4 GHz64 QAM激励下,输出功率可达19.8 dBm,满足标准规范要求.     

基于时域RF-DNA的功率放大器射频指纹识别

射频(RF)功率放大器是辐射源射频指纹特征产生的关键器件之一,是射频指纹(RFF)产生机理和个体识别的重要突破口。设计一种功率放大器射频指纹提取实验方法,利用时域射频独特原生属性(RF-DNA)方法成功提取了功率放大器的射频指纹,并对RF-DNA指纹进行了可视化处理。研究结果表明,功率放大器的射频指纹主要反映在幅度失真特性上,利用瞬时幅度生成的时域RF-DNA指纹能够实现对放大器个体的分类,在信噪比大于12 dB时,分类正确率在91%以上。可视化后,能直观观察RF-DNA指纹及不同功率放大器之间统计特征的相似性和差异性。     

一种高功率小型射频放大器研究

本文根据高功率射频功率放大器的基本特性,研究了工作频率在100MHZ左右,功率等级在2KW左右的峰值功率,平均功率在200W左右的射频功率放大器,利用无源集中参数和微带混合结构匹配方式实现阻抗匹配,该方式具有匹配简单,物理结构整洁,同时不牺牲功率放大器性能。实验表明,该小型化功率放大器缩小尺寸一半以上,峰值功率1dB压缩点在2KW,大信号增益为30dB,具有良好的线性度,效率大于60%。     

航天测控高效率线性功率放大器研究

针对航天测控发射机的GaN末级功率放大器效率得到提升,但线性度往往达不到指标要求的问题。提出了射频预失真技术和Doherty技术相结合的方法来提高功率放大器的回退效率和线性化指标,给出了射频预失真的方案设计,对差分匹配和100 W功率放大器进行了仿真设计。通过仿真分析和试验可以发现,该方法可以改善三阶交调到-47 dBc以下,效率在输出功率回退6 dB后可以达到45%。     

射频SOI LDMOS功率放大器设计与仿真

简介了改进的绝缘层上硅横向扩散金属氧化物一半导体(SOI LDMOS)电路模型.根据改进的SOI LDMOS电路模型,采用射频仿真软件进行了射频功率放大器的设计与仿真.该射频功率放大器采用两级放大结构,采用了S参数设计方法和负载牵引方法设计.结果表明放大器的增益达到15 dB,输出功率达到25 dBm,功率附加效率大于40%.     

An automatic-gain-controlled Raman fiber amplifier/gain-clamped SOA for metro WDM networks with changes in span loss

We propose an automatic-gain-controlled Raman fiber amplifier/gain-clamped semiconductor optical amplifier. The amplifier uses a feedforward gain-control scheme to maintain the channel output power. The signal power after the optical amplifier is automatically controlled to within 0.15 dB when the span loss changes from 16 to 26 dB.     

K频段自适应前馈行波管放大器设计

空间通信系统高保真转发对大功率行波管放大器的线性化度提出了更高的要求。针对高频段和大功率应用,基于预失真和前馈线性化技术,设计了一种K频段50 W 自适应前馈线性化行波管放大器,介绍了其基本原理和参数,研究了前馈双检波电路结构及并行变步长的组合自适应控制算法。在K频段400 MHz带宽内,实现了输入功率20 dB 大动态调整情况下失真信号自适应对消抑制,在相对于单载波饱和输出功率回退3 dB 点,三阶交调小于-35 dBc,验证了前馈线性化技术在线性度改善方面的巨大优势。     

Characterization of a low-noise linearized microwave power amplifier module

An X-band, low-noise, linearized microwave power amplifier module consisting of a low-noise solid-state amplifier (SSA), predistortion linearizing circuit, and low-gain helix traveling wave tube (TWT) is designed and tested in order to demonstrate both reduced noise figure and suppressed intermodulation distortion ratio. Two-tone intermodulation distortion (IMD) ratios are predicted from simulations obtained from modeling of the TWT, linearizing circuit, and SSA by the use of Agilent's Advanced Design System simulation code. Simulated IMD ratios are in good agreement with measured results. Measurements show a noise figure of 2.2 dB at 9.5 GHz and the third-order IMD ratio of -53 dBc at 10 dB input back off from the input P1dB point. It is found that both noise figure and IMD ratio are significantly improved compared with conventional helix-TWTs and microwave power modules.     

数字自适应前馈功放线性化研究

本文研究了一种新的前馈线性化功放的结构,省去了导频信号,在经典的两环前馈法基础上引入第三环,通过第三环直接提取交调信号,同时在线性化功放系统中引入了DSP控制器,用最优化算法进行控制,实现了对线性化功放的自适应控制。此方案被用于cdma2000基站功放的设计,使三载波CDMA信号输出的ACPR低于-51dB。     

A feedforward S-band MIC amplifier system

A 2.2 GHz high-power feedforward amplifier system has been designed and fabricated, which has an RF gain of 30 dB and delivers an output power of 1.25 W with all IM distortion products at least down 50 dB from the carrier level. The power amplifiers and passive circuit components used in this system are all realised in thin-film hybrid form. The theoretical development of the system is described. The result of the temperature stability tests is given. The computer optimisation technique with multiband weighting functions used throughout the amplifier design process is presented. Finally, practical applications and a comparison of the advantages and drawbacks of this (feedforward) amplifier system with those produced by using the conventional (back-off) approach are discussed.     

Performance evaluation of COFDM for digital audio broadcasting. II.Effects of HPA nonlinearities

For pt. I see ibid. vol.43, no.1, p.64-75, 1997. The effects of the high power amplifier (HPA) nonlinearities on the performance of the Eureka 147 DAB system are studied by computer simulation. The performance is determined for three types of HPA: a travelling wave tube amplifier (TWTA), a solid state power amplifier (SSPA) and a perfectly linearized amplifier (PLA). Two related performance criteria are used: (a) the degradation, resulting from HPA nonlinearities, in the E_b /N₀ ratio required at the receiver to maintain a bit error rate of 10^-4 and (b) the total power degradation. These degradations are measured as a function of the HPA output backoff (OBO). The effect, on the E_b/N₀ degradation, of linearizing only the phase or only the amplitude transfer characteristic of the TWTA and the SSPA is also assessed. Correcting the phase distortion alone in both HPAs is found to reduce the E_b/N₀ degradation by less than 0.5 dB. Linearization of the amplitude characteristic alone, on the other hand, can reduce the E_b/N₀ degradation by several dBs at small OBO values (<2 dB). The optimum output backoff which minimizes the total power degradation is between 2 and 3 dB for both the TWTA and the SSPA in a terrestrial mobile channel and between 1 and 2 dB in an AWGN channel. The optimum output backoff for the PLA is 2 dB in the terrestrial channel and between 1 and 2 dB in the AWGN channel. At the optimal operation point, the power saved by linearizing the amplitude and phase characteristics of the TWTA or the SSPA is about 0.6 dB for the terrestrial mobile channel and 0.4 dB for the AWGN channel     

射频功率放大器的自适应前馈电路设计

先分析常用双环自适应前馈电路降低非线性失真及输出功率的特点和不足,通过引入另一个前馈电路,从主功率放大器的输入端耦合部分信号到辅助功率放大器的输入和输出端,经适当调节,进一步改善电路的三阶交调失真(IMD3),并增大输出功率.结果显示,这种改进的自适应前馈电路,IMD3低于信号功率-75dBc,线性度改善效果明显,而且输出功率增大了2～3dB.     

A 5.7–6.4GHz GaAs HBT Power Amplifier with a Gain Enhanced Bias Circuit

This paper describes the design of a 5.7–6.4GHz GaAs Heterojunction bipolar transistor (HBT) power amplifier for broadband wireless application such as wireless metropolitan area networks. A bias circuit is proposed which enhances the power gain and provides a good linearity. Using the wideband matching network tech-niques with trap circuits embedded to filter the harmonics and the diode-based linearizing techniques, a broadband power amplifier module was obtained which exhibited a gain above 28dB. This is about 1dB improvement com-pared with those normal bias circuits at a supply volt-age of 5V in the frequency range of 5.7–6.4GHz, measured with Continuous wave(CW) signals. The saturated output power was greater than 33dBm in 5.7–6.4GHz and the out-put 1dB compression point was greater than 31dBm. The phase deviation was less than 5 degrees when the output power below 33dBm. The second and third order harmonic components were also less than -45dBc and -50dBc.     

一个利用线性区MOS管补偿的射频放大器

研究了一种采用线性化技术的低电压CM O S射频放大器。电路中,并联一个工作在线性区的M O S管来提高其线性。采用SM IC的0.18μm工艺,流片测试结果显示,该电路用很小的功耗代价将放大器的输入三阶交截点功率提高了大约5 dB。     

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.