翻译.doc

请求各位大哥帮我看看这篇论文的翻译还有什么修改的，毕设老师老师说翻译的太差，需要重新修改...
谢谢大家...

外文资料原文
Ka-Band LNA Module with 1.9dB NF for Communications Satellite Payload
D. P. Chang1, I. B. Yom1, S. H. Oh2
1 Electronics and Telecommunications Research Institute
161 Gajeong-dong, Yuseong-gu, Daejeon, 305-700, Korea
2 Chungnam National University
220 Gung-dong, Yuseong-gu, Daejeon, 305-764, Korea

I. INTRODUCTION
Commercial space applications at Ka-band are currently in production and require low noise performance to meet the system G/T specifications . In the past the low noise equipments in the Ka-band satellite payload had been developed using discrete FET devices. However, LNA MMIC chips with about 1.5dB NF are recently available  and it allows of developing low noise module with very small size. The use of MMIC chips has the advantage in production with little effort in tuning process. Several cases using Ka-band LNA MMIC for satellite payload have been reported .
A LNA module of EM(engineering model) grade was developed with two LNA MMIC chips fabricated by using a space-qualified MMIC foundry. The first LNA MMIC is an ultra low noise amplifier with single-ended two-stage structure and the second LNA MMIC is a wide band low noise amplifier with balanced two-stage structure.
A key challenge for Ka-band LNA module to use in satellite payload is the need for low loss and hermetic RF transition to minimize the impact on noise figure while maintaining reliability. For the development of the transition, a coaxial hermetic bead with a probe cap was used for broad bandwidth and the transition loss was minimized by using precision machining and assembly techniques. The transition structure had been analyzed by using the commercially available 3D electromagnetic simulation tool.
The developed module has the size of 56mm X 35mm X 24mm and the mass of 94grams including input waveguide
II. ELECTRICAL DESIGN
This Ka-band Low Noise Amplifier (LNA) is a receiver preamplifier providing low noise to minimize impact on system G/T and high gain to shield the noise contribution from the rest of the satellite payload.
The performance requirements for the module are summarized as shown in Table I. The noise figure performance of the requirements is the most difficult target to meet in the present state of art technology in Ka-band.
To enhance the G/T performance of the payload system, the LNA module will be integrated near the antenna feed assembly. Therefore, it is very important that the module should be manufactured with small size and mass for the payload integration.
The RF input and output are WR-28 waveguides providing a low-loss interface with the receiver section of satellite payload.
The module consists of two MMIC amplifier chips, a waveguide isolator, and a drop-in type isolator. The waveguide isolator is assembled outside of the module body. The waveguide-to-microstrip transition is manufactured as a part of the module body. Fig. 1 shows the block diagram of the designed module
A. MMIC Amplifiers
All MMIC amplifiers had been fabricated in 0.15um GaAs pHEMT foundry with space-qualified process.
The first MMIC amplifier is an ultra low noise amplifier and has single-ended wo-stage structure. Feedback microstrip lines at sources of HEMT are used to provide the trade-off between gain and noise figure. The unit device is a HEMT with 4 fingers and gate width of 80 um. The fabricated MMIC chips have 1.7dB of noise figure and 18dB of gain over the frequency range of 26 ~ 30GHz. The performances have been measured under the DC condition of 2.6V and 18mA. The chip has been realized with the size of 2.5mm X 1.5mm. Fig. 2 shows the measured NF and Gain for the test jig of the first LNA MMIC chip. The graph includes as much as 0.5dB of jig loss.
The second MMIC amplifier is a wide band low noise amplifier and has balanced two-stage structure. Lange couplers are used at the input and output to realize wideband return loss performance. Series feedback technique for the HEMT in the first stage is used to improve input return loss matching and low noise matching, and to enhance the amplifier stability. Shunt feedback technique for the HEMT in the second stage is used to get the full band stability and wideband performance. The fabricated chips show the gain above 17dB and noise figure below 2.7dB in the frequency range of 23 ~ 32GHz. Return loss is above 20dB in the frequency range. The performances have been measured under the DC condition of 2.3V and 60mA. The chip size is 3.0mm X 2.2mm.
B. Waveguide-to-microstrip Transition
Because the loss of the transition at input of the module is added directly to the noise figure, the design and manufacturing of the transition should consider the transition loss to be minimized while maintaining reliability. A transition with an E-plane coaxial pin/probe configuration and in-line structure has been designed to provide the flexibility in payload configuration and a coaxial hermetic bead has been used to provide structural stability and reliability.
The 3D model used for electromagnetic simulation is shown in Fig. 3. From the simulation result the return loss below 25dB was obtained over 28 ~ 31GHz range and from the test result of the verification jig the insertion loss about 0.4dB was achieved over 29.5 ~ 30.1GHz range without tuning.

C. Isolators
A waveguide isolator is used to prevent the distortion in gain response caused by the interaction after the module connection with other component at the input and maintain low VSWR performance. At the output a drop-in isolator is used to save the housing space and protect the module from the unwanted effects caused by next component in payload. The waveguide isolator with insertion loss less than 0.15dB and the drop-in isolator with insertion loss less than 0.9dB have been used in developing the LNA module. Those isolators would be supplied from a space-qualified manufacturer for the qualification model.
D. DC Bias Circuit
DC bias circuit is required to supply DC voltage and current to those amplifiers in the module. The circuit was designed using active bias scheme with BJT and fabricated on 25mil thick alumina substrate by using thickfilm technology. In the circuit, a thermistor is used to compensate the gain variation over temperature by controlling the current for the second amplifier
外文资料译文
用于通信卫星的1.9dB噪声系数的Ka波段低噪放大器
1介绍
在Ka波段的商业空间应用目前正在生产，它需要低的噪声系数来满足系统G/T规格。过去，在Ka波段的卫星有效载荷中，低噪声设备已经有用分立的场效应管设计出来了。然而，噪声系数为1.5dB左右的低噪声放大器的微波单片集成电路芯片只是在最近才已经实用的，并且它是很小的尺寸的低噪声组件。在生产中有微弱的调谐处理时，使用MMIC 芯片有一定的优势。在卫星有效载荷中使用Ka波段LNA MMIC的一些情况已经被报道了。
一种工程模式级LNA组件已经利用在空间中用合格的单片晶圆代工构造的两块LNA的MMIC芯片设计出了。第一个LNA MMIC是一个单端型两级结构的超低噪声放大器，第二个LNA MMIC 是一个平衡的两级结构的宽带低噪声放大器。
在卫星有效载荷中应用Ka波段的LNA 的关键难题的是需要低的损耗以及全密封的射频转换，以便在保持可靠性的同时减小对噪声系数的影响。由于这种转换的发展以及宽带需求，一种带有探针帽的同轴封闭珠子被应用了，这样转换损耗也由于采用精确的加工和组装技术而减小了。这种转换结构已经利用商业有效的3D电磁场仿真工具进行了分析。
这种组件拥有56mm×35mm×24mm的尺寸大小以及包括输入波导隔离器在内的大部分质量。
这边论文描述了电磁和机械设计，制造技术，以及测试结果。
II.电子设计
这个的Ka波段LNA是一个接受系统的前置放大器，它提供低的噪声来减小对系统G/T影响和高的增益来防止来自于卫星有效载荷的其余部分的噪声的影响。
在表1中总结出这种组件的设计要求。现阶段Ka波段设计技术中，这样的设计要求中噪声系数特性是最难实现的目标。
为了提高有效载荷系统的G/T特性，这个LNA组件将被集成在天线反馈的周边。因此，较小的体积和大量的有效载荷的集成来制造这样的组件就是非常重要的。
射频信号的输入和输出都是使用WR-28的波导，这种波导在卫星有效载荷的接收块处提供了低损耗的表面。
这个组件由两个MMIC 放大器芯片，一个波导隔离器和一个插入式的隔离器组成。这个波导隔离器装载组件的外围。波导到微带线的转换器是作为组件本身的一部分生产的。图1为设计组件的框图。
直流电路板的设计和组装是用来对组件里的MMIC放大器提供稳定的偏置。
A. MMIC 放大器
所有的MMIC 放大器都是在0.15um 的GaAs PHEMT 管子设计的。
第一个MMIC 放大器是一个超低噪声的放大器，它是单端型两级结构。HEMT管的源端的反馈微带线是用来提供增益和噪声系数的平衡。这个唯一的器件是一个有四端口和80um门宽度的HEMT 管子。这种构造的MMIC 芯片在26—30 GHz频率范围内有1.7dB 的噪声系数和18dB的增益。这些特性是在2.5V和18mA 的直流条件下测试得到的。这种芯片已设计大小为 2.5 mm×1.5 mm 。图二展示了第一个LNA  MMIC 芯片的测试 噪声系数和 增益大小。这张表格同样包括了0.5 dB的损耗。
第二个MMIC 放大器是一个宽带的低噪声放大器，它拥有平衡的两端结构。Lange耦合器用来在输入输出端来实现宽带的回波损耗特性。第一个级的HEMT 管的串联反馈技术是为了改善输入端的回波损耗匹配和低噪声匹配，并且提高放大器的稳定性。第二个级的HEMT 管子的并联反馈技术是为了得到全频带的稳定性和宽带特性。这种构造的芯片表明在23-32GHz 的频率范围内有大于17dB的增益和小于2.7dB 的噪声系数。在这样的频带范围里回波损耗也高于20dB。这些特性是在2.3V, 60 mA 的直流条件下测试的。这样的芯片大小是3.0 mm ×2.2mm。
B波导到微带的转变
因为这种组件在输入端的转换损耗是直接加在噪声系数上的，这种转换模式的设计和生产就需要考虑减小转换损耗并且同时保持可靠性。一种Ｅ面的同轴探针构造和轴向结构的转换器被设计来提供在有效载荷结构的适应性，同轴密封的小珠被用来提供结构的稳定性和可靠性。
图3给出了电磁仿真的3D 模型。从仿真结果中，我们可以看到回波损耗在28-31GHz频带范围内回波损耗小于25dB, 从测试的结果中，我们得到在没有调谐的情况下，在29.5-30.1GHz频带范围内，插入损耗为0.4dB 。
隔离器  
该波导隔离器用来防止由于该组件在输入端与其他元件连接而引起的相互干扰的增益响应失真以及保持低的电压驻波比特性。在输出端的插入式隔离是用来减小空间大小和防止由于有效载荷中的下一个器件而产生的不必要的影响。具有小于0.15dB 的损耗的波导隔离器，和另一个损耗小于0.9dB的插入式隔离器被用来组成LNA 组件。这些隔离器将由一个空间适用的生产商提供。
D直流偏置电路
直流偏置电路是在放大器组件中用来提供直流电压和直流电流的。该电路是利用含有BJT的有源偏置电路图来设计，并且利用厚膜技术在25 mil 厚度的底板上制造。在这个电路中，一个热敏电阻通过控制第二个放大器的电流从而补偿由于温度变化而受影响的增益变化。

信达雅　　信达雅
　　【注音】：xìn/shēn dá yǎ
　　【释义】：1.翻译作品内容忠实于原文谓信，文辞畅达谓达，有文采谓雅。语出严复《天演论》。
　　何谓“信”“达”“雅”？它是由我清末新兴资产阶级启蒙思想家严复提出的，他在《天演论》中的“译例言”讲到：“译事三难：信、达、雅。求其信已大难矣，顾信矣不达，虽译犹不译也，则达尚焉。”“信”指意义不背原文；“达”指不拘泥于原文形式‘“雅”则指追求文章本身的古雅。

太高深了  发现我没有那样的水平 关键是有些专业词汇不知道翻译，自己就觉得翻译的不对，还有就是基础太差，感觉从句，简单的后置定语无法翻译...像 with...in...

哪位大哥帮我看看的啊 老师说他看不懂我是怎么翻译的 可是我的水平就是这样，我怎么翻译的啊

如果每个词的意思都翻译正确的话，你只需修改你的翻译就行
就是说，你看你翻译后的文章，然后用正常的表达方式重新写一遍
中文的语序和英文不一样，要注意

首先不提你翻译的是不是准确

你的中文基本上就读不通，呵呵，请原谅我如此直接的表达

一般的翻译都是拿给中国人看的，要注意中文表达；建议先读一段，然后抓住中心意思后在进行意译

呵呵

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