complex的博客

From: http://compoundsemiconductor.net/cws/article/magazine/34662 DARPA's funding has made a staggering contribution to the compound semiconductor community. Novel materials and devices have flowed forth from its programs and opened up lucrative markets for military and commercial applications. Richard Stevenson looks back at the agency's first 50 years. It's hard to imagine where we would be without the US Defense Advanced Research Projects Agency (DARPA). Decades of funding haven't just he...

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From: microwaves101.com History of Coplanar Waveguide Coplanar waveguide was invented by Cheng P. Wen. It was invented when Wen was at RCA's Sarnoff Laboratories in New Jersey, way back in 1969, just two years after the Summer of Love... Dr. Wen now lives in Beijing, and continues to pass on his considerable knowledge to microwave engineering students, and he has corresponded with Microwaves101 on the topic of CPW (how's that for name dropping?) C.P. Wen explains that his original "name" for...

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From: compoundsemiconductor.net  The 324 GHz single stage InP amplifier is an important landmark for SWIFT, the DARPA program hoping to develop advanced imaging systems. High-frequency InP transistors have made a key breakthrough for high-resolution, all-weather imaging, as they have been used to produce the first sub-millimeter wave DHBT monolithic amplifier. Jonathan Hacker of Teledyne Scientific presented the InP DHBT MMIC, at the MTT-S International Microwave Symposium in Atlanta on...

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当然就是匹配网络了。首先看看在HPA MMIC中，匹配网络的作用： Present the optimum source and load impedances to the transistors; Divide or combine the RF power; For the input and interstage-matching network, realise a frequency dependent loss; Supply the DC bias to the transistors; Enhance the stability of the amplifiers. 这最基本的五条，看似简单，但是任意一条拿出来都可以说上一大堆Design Options，比如DC Bias：在MMIC中首先要根据电流大小及金属的最大可承受电流密度，计算其宽度下限，然后再选定宽度的基础...

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  The following methods to determine the optimum load impedance were considered: (1). The use of the so-called Cripps method. This method uses a simplified model of the transistor, which can be obtained from small-signal S-parameter measurements at the bias point of interest and knowledge of the DC IV curves. With the help of this information it is possible to construct load-pull contours and the optimum load impedance can be determined. The Cripps method was not used because of the f...

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From: compoundsemiconductor.net Cree and TriQuint have both rolled out competing GaN foundry services amid strong interest in the high-power RF technology at the 2008 International Microwave Symposium. In each case military applications are providing a strong driving force in developing GaN devices, attracted by characteristics like high power density and high-temperature operation. Both companies are still involved in DARPA's Wide Bandgap Semiconductor Technology initiative, with TriQuint i...

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From: eetchina.com LTE和WiMax之间唯一最重要的相似性在于均采用正交频分复用(OFDM)信令。两种技术也均采用Viterbi和turbo加速器来实现前向纠错。 从芯片设计工程师的观点来看，如果你要在同一芯片或芯片组内支持两种制式的话，就非常有可能广泛地重用各种门。从软件无线电(SDR)的观点来看，机会更为诱人。灵活性、门重用以及可编程性似乎就是应对WiMax-LTE多模式挑战的答案，而那可能意味着要采用软件无线电技术。 LTE和WiMax可能就是OFDM这颗“蚕豆”上的“两片豆子”，但是，它们并不是孪生的。它们之间存在三个重要差异： 1. 两者...

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1. Determine Optimum Bias Point for Required Output Power; 2. Design of Biasing Network; 3. Transistor Stability Analysis, Zsource Calculation for MAG; 4. Load-pull Analysis to Determine Optimum Zload for Required Pout; 5. Design of Matching Network; 6. Optimization, Yield Analysis and Design Centering; 7. Layout Gneration (EM Analysis); 8. Verification for Wireless Communication Standard.

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长叹一口气......该死的VBIC模型，终于可以不再折磨我那少得可怜的脑细胞了。 湖哥走的时候将MMIC PA的工作留给我，到现在他毕业整整一年了，但是工作几乎停滞不前。电路的拓扑结构和工艺早就OK了，但是在设计的时候没有HBT器件模型，没有Load-pull测试数据--当我试图去做这些的时候，我们微波探针台上的探针挂了，Load-pul只要一加电就振荡。知道上月，卡尔休斯的探针和新的Load-pull系统都到位，于是数据搞定了。测试比较简单--只要你有测试手段，问题是测试之后的数据处理，譬如提取模型参数、设计匹配网络等等。 那么，当下最要紧的是...

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From: compoundsemiconductor.net Cracks are starting to appear in silicon CMOS. Although the International Technology Roadmap for Semiconductors states that MOSFETs with strained silicon channels will be suitable down to the 22 nm node and possibly beyond, projections of device performance indicate otherwise. Studies show a gap will appear between projected and actual performances as node sizes fall to less than 65 nm, and this will only get wider with increased scaling (figure 1). To make ma...

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微电子所研制成功高性能Ku波段功率放大器模块      近日，微电子所在新型微波功率放大器模块研究领域获得突破性进展。中国科学院微电子研究所—四川龙瑞微电子联合实验联合研制成功的Ku波段功率放大器模块，在13.7-14.5GHz频率范围内，功率增益 ，输出峰值功率 ，总工作效率达到13.6%。该模块有效体积为 ，总体重量为 ，并且通过了严格的高低温可靠性测试，关键技术指标都达到了国内一流水平。     该模块采用结构简单并且可靠性高的平面微带线完成微波链路，有效减小了重量和体积。在机械结构上设...

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好长时间没有更新Blog了，看paper看得满脑子都是VBIC了，今天灌一篇，说一下测试和建模。 S参数测试中的去嵌入问题，以前觉得挺高深的，但是实际做过之后也不觉得有多困难了--当然，如果精度要求很高的话就另当别论了。在画版图的时候，除了器件之外一般还要有用于去嵌入的Open和Short图形，Open图形用来去除寄生电容的影响，Short图形用来去除寄生电感和电阻的影响。去嵌入的一般步骤如下： （1）测量Open图形的Y参数[Yo]与Short图形的Y参数[Ys]； （2）用[Ys]减去[Yo]，得到：[Yso]=[Ys]-[Yo]； （3）将[Yso]换为Z参数[Zso]，得到互连线...

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From: compoundsemiconductor.net The emerging market for so-called femtocells will explode over the next five years, providing a key new application for power amplifier (PA) components, and a likely boost for makers of GaAs devices. Reports from ABI Research, In-Stat and Wintergreen Research all predict a sharp increase in deployments of femtocells, with accompanying demand for the various semiconductor components that they require. Femtocells, which are miniature cellular base stations, are ...

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From: compoundsemiconductor.net RF Micro Devices is to cease development of transceivers for next-generation handsets and sell off its GPS solutions business, reducing its headcount by 350 employees. The GaAs chip maker estimates that the move will save it $75 million annually, largely from the decision not to plow research resources into development for broadband wireless transmission protocols, like wideband CDMA, Long-Term Evolution (LTE) and WiMAX. Although the move will cost $40 million...

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Skyworks attributes part of its recent success to strategically developing its business with specific partners, like acquiring a supply deal with Blackberry manufacturer Research in Motion through its purchase of Freescale’s GaAs handset PA business. Although Sony-Ericsson, Motorola and Samsung each account for more than 10 percent of Skyworks' business, the company is also in the middle of a major ramp for wideband-CDMA PAs for Nokia. It claims to be the only PA maker that sells products...

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