宽带无线通信射频收发前端设计

介绍了一种宽带无线通信系统(BWCS)。提出了一种应用于该系统TDD模式射频(RF)子系统设计方案,并对RF子系统进行了分析。研制出射频子系统电路,给出了测试结果。测试结果表明研制的RF子系统各项指标都满足宽带通信系统的设计要求。     

Photo-injection p-i-n diode switch for high-power RF switching

The high RF power-switching properties of the photo-injection p-i-n switch (PIPINS), an optically controlled RF switch, are investigated. Proper functioning of a PIPINS as a low insertion-loss RF switch requires that it operates as a photoconductor, where the photo-injected charge is much greater than the RF sweep out charge. Insertion loss using 650-mW optical power was <0.4 dB at RF (VHF-UHF) power in excess of 200 W, and devices successfully standoff 200-W incident RF power with the series isolation being determined by the device capacitance (e.g., 225 fF). PIPINS hot-switching measurements are reported for the first time, with output RF power up to 180 W at low duty cycle, rise times of 1 ps, and fall times for a series shunt switch of ≈2.5 μs. The RF power for hot switching a PIPINS is limited by a latch-on effect, which is dependent on a variety of parameters, including duty cycle and repetition period, consistent with thermally generated carriers contributing to the latch-on effect. The switching properties of PIPINS make them a candidate for high RF power applications such as reconfigurable antennas, where electromagnetic isolation of the switch and control lines are critical     

射频技术在物联网中的应用

随着当今科技的迅速发展,非接触式射频传感作为一种新型的网络技术,在物联网中射频技术具有非常重要的作用,在越来越多的领域中得以应用。共享和交换信息是通过具有开放性的计算机网络来实现的,利用射频技术,物联网能够有效管理物品。利用空间电磁场和射频信号耦合传输特性,自动识别与交换监控物体信息,这就是射频技术基本原理。基于射频技术的原理,对射频技术实现的系统结构与技术手段做出一定的分析,并通过流程图展示射频技术运作原理。最后对物联网中应用射频技术进行了探讨,并通过图例对射频技术在物联网中核心技术的实现过程做出一定的解析,为今后解码运用射频技术实现在物联网中运作过程给出了一定的借鉴意义。     

射频功率放大器告警功能模拟检测方案

射频功放模块是基站系统中的核心部件,出厂前对射频功放模块的功能进行检测意义重大.设计了一块告警功能测试板,通过观察与射频功放模块相连的测试板上的LED灯,判断射频功率放大器功能是否正常.实践证明,该方法能模仿射频功率放大器在实际基站系统中的工作行为,不仅有效地提高了射频功率放大器的良品率,而且适用于商业化大规模批量生产...     

InGaP HBT 大信号RF功率传输特性

本文实验研究了用于RF功率放大器的先进的InGaP HBT 器件大信号RF功率传输特性。研究了InGaP HBT在小信号和大信号状态下输出端的发射功率和反射功率及输入端的反射功率的规律。分析了InGaP HBT RF功率信号的多频率功率成份及其对大信号功率增益压缩,非线性和RF输出功率饱和的影响。     

Large signal RF power transmission characterization of InGaP HBT for RF power amplifiers

The large signal RF power transmission characteristics of an advanced InGaP HBT in an RF power amplifier are investigated and analyzed experimentally. The realistic RF powers reflected by the transistor, transmitted from the transistor and reflected by the load are investigated at small signal and large signal levels. The RF power multiple frequency components at the input and output ports are investigated at small signal and large signal levels, including their effects on RF power gain compression and nonlinearity. The results show that the RF power reflections are different between the output and input ports. At the input port the reflected power is not always proportional to input power level; at large power levels the reflected power becomes more serious than that at small signal levels, and there is a knee point at large power levels. The results also show the effects of the power multiple frequency components on RF amplification.     

机载射频系统地面试验外场建设的新思路

介绍了国外机载射频系统的组成,分析了机载射频系统的战技指标,探讨了国外试验 外场的设计和设备配备。借鉴国外经验,总结了机载射频系统测试内容,提出针对 机载射频系统地面测试外场建设的新思路,为工程实施奠定基础。     

Comparison of power deposition patterns produced by microwave andradio frequency cardiac ablation catheters

Transcatheter microwave and radio frequency (RF) electrodes are used for the ablative treatment of cardiac arrhythmias. The authors compare the power deposition patterns of microwave antennas and RF electrodes in saline phantoms of biological material. The decrease in power deposition as a function of distance away from the electrode is nearly exponential for RF and is considerably steeper than microwave antennas. These results suggest that microwave antennas are capable of heating a larger volume and thus creating a greater lesion than RF     

射频集成电路测试技术研究

射频集成电路(RFIC)是无线通信、雷达等电子系统中非常关键的器件，由于其高频特点，准确评估RFIC的性能具有相当的难度。文章以射频低噪声放大器(LNA)为例，运用微波理论，分析了RFIC典型参数，如S参数、带宽、PldB、OIP3以及噪声系数等的测试原理和测试方法，并对影响RFIC性能测试的主要因素进行了分析。最后，给出了一种LNA电路的测试结果。     

射频激励CO_2激光器的阻抗匹配及调制的实验研究

论述了射频（ＲＦ）激励气体放电所必须的在ＲＦ源与激光头放电气体之间的阻抗匹配器的工作原理及其实验，并依据研制成功的千瓦级ＲＦ激励快轴流ＣＯ２激光器的实际参数，论证了气体放电阻抗的计算、动态阻抗调配及ＲＦ泵浦调制的激光实验。     

RF MEMS的关键技术与器件

文章介绍了RF MEMS的基本概念、基本特征与关键工艺技术。文章在介绍了RF-MEMS 元器件的基础上,对RF MEMS与MMIC进行了比较,分析了RF MEMS需解决的重点问题。最后对 RF MEMS的发展前景进行了展望。     

RF ESD protection strategies: Codesign vs. low-C protection

The present work is focussed on the trade-off between conventional RF ESD protection concepts optimized in terms of capacitive load and the frequently discussed RF ESD codesign idea with ESD protection skilfully integrated into RF circuit design. A narrow and a broadband RF test circuit were developed to put the benchmark on a firm basis. RF and ESD experiments are discussed, showing where the higher effort for the codesign approach starts to pay off.     

浅析CDMA网络射频优化方法

网络优化是移动通信网络建设中一个非常重要的环节,其目的就是要改善网络的通信质量。射频(RF)部分的优化是网络优化的一个重要组成部分,通过对射频部分进行调整,调整射频参数,可以明显改善网络质量。文中描述了网络优化中的RF优化,详细描述了影响网络性能的天馈参数和其他系统参数,通过介绍整个RF优化流程,说明如何对这些参数进行调整以获得网络质量的改善。     

Verification of Complex Analog and RF IC Designs

Meeting performance specifications in the design of analog and RF (A/RF) blocks and integrated circuits (IC) continues to require a high degree of skill, creativity, and expertise. However, today's A/RF designers are increasingly faced with a new challenge. Functional complexity in terms modes of operation, extensive digital calibration, and architectural algorithms is now overwhelming traditional A/RF design methodologies. Functionally verifying A/RF designs is a daunting task requiring a rigorous methodology. As occurred in digital design, analog verification is becoming a separate and critical task. This paper describes the verification issues faced by the A/RF designer and presents a verification methodology to address these challenges. It presents a systematic approach to A/RF verification, the concept of an analog verification engineer, how to establish the methodology, and concludes with an example     

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.     

基于层次分析法的射频隐身性能评估

针对系统的射频隐身性能评估问题,首先提出了射频隐身的评估指标体系并对指标进行归一化模糊处理;然后,利用层次分析法确定了各指标的权重,并建立了三级评估模型,实现了射频隐身性能的量化评估;最后,对两种系统的射频隐身性能进行了模糊综合评估。实例分析结果表明:该射频隐身性能评估模型有效可行,其评估结果可为系统的射频隐身设计改进提供参考。     

A Subthreshold CMOS RF Front‐End Design for Low‐Power Band‐III T‐DMB/DAB Receivers

This letter presents a CMOS RF front‐end operating in a subthreshold region for low‐power Band‐III mobile TV applications. The performance and feasibility of the RF front‐end are verified by integrating with a low‐IF RF tuner fabricated in a 0.13‐μm CMOS technology. The RF front‐end achieves the measured noise figure of 4.4 dB and a wide gain control range of 68.7 dB with a maximum gain of 54.7 dB. The power consumption of the RF front‐end is 13.8 mW from a 1.2 V supply.     

RF and IF ports matching circuit synthesis for a simultaneousconjugate-matched mixer using quasi-linear analysis

A quasi-linear two-port approach between RF and IF ports to design a simultaneous conjugate-matched mixer is presented in this paper. Conventionally, mixer design is treated as a nonlinear three-port device problem. Nonetheless, with the exception of the large-signal local oscillator (LO) that exists at the LO port, the input RF and output IF signals that exist at the RF and IF ports, respectively, are small signals. Consequently, mixers can be approximated as bilateral quasi-linear two-port circuits with a time-variant transfer function between the RF and IF ports, in which the LO port of the mixer is treated as part of the two-port network. With this approximation, it can be shown mathematically that the optimum source and load matching networks required for attaining simultaneous conjugate match at the RF and IF ports are actually time invariant, thus implying that it is possible to synthesize these optimum impedance values. This proposed mixer design technique, together with the equations derived, are verified with block-diagram simulation and experimental measurements of two 2.4-GHz RF/420-MHz IF double-balanced diode mixers     

A simple four-terminal small-signal model of RF MOSFETs and its parameter extraction

After differences between the RF MOSFET and conventional high-frequency transistors, which make the proper modeling of RF MOSFET complicated and difficult, are addressed, a four-terminal small-signal model of an RF MOSFET with a very simple and accurate parameter extraction method is presented. This model includes the intrinsic and extrinsic elements important for RF AC simulation in the strong inversion operation region. Accuracy of the model and extraction method is verified with the measured data and the needs of the intrinsic body node are demonstrated to describe the gate bias dependence of the substrate-signal-coupling effect.     

Approximations for the renewal function

This paper describes an accurate, computable approximation for evaluating the renewal function (RF). The method uses Pade approximants to compute the RF near the origin and switches to the asymptotic values farther from the origin. There is a polynomial switch-over function in terms of the coefficient of variation of the distribution, enabling one to determine a priori if the asymptotic value can be used instead of computing the Pade approximant. The results are tested with the truncated Gaussian distribution. The method yields a set of approximants to the RF that are re-usable, and can be used to compute the derivative and the integral of the RF. Results for the RF are within 1% of the optimal solution for most coefficients of variation