【作者】 刘凯；

【导师】 郭高凤；

【作者基本信息】 电子科技大学 ， 电路与系统， 2014， 硕士

【摘要】 作为工作在大信号状态下的微波真空器件,行波管放大器(TWTA)凭借高功率、高增益、宽频带和高工作频率等性能特点,广泛应用于深空探测和电子对抗等无线通信领域,并在其中扮演着将信号进行放大的重要角色。由于TWTA是一种非线性器件,大信号条件下表现出的非线性幅相(AM-AM、AM-PM)效应会对整个系统的通信质量造成影响。基于此,有必要建立测试模块,对TWTA的AM-AM、AM-PM行为进行测试和预判,根据测试的结果,对TWTA进行线性化处理。本文立足TWTA测试的基本原理,首先对TWTA的非线性幅相测试在国内外的研究现状进行调研,通过对幅相测试系统的深入了解,综合制作成本、在线测试和测试精度等因素,采用了六端口电路实现TWTA幅相测试模块。对六端口的原理进行推导,印证了采用该测试模块作为非线性幅相测试部件的合理性。本文从以下几个方面对测试模块进行了研究和设计:1.结合幅相测试模块基本原理,确定了采用多节非对称形式耦合器作为取样耦合器的方案。通过对传统多节耦合器的对称和非对称结构进行理论研究,研制了改进形式的10dB非对称定向耦合器,测试结果表明:在2~18GHz内,耦合度在10dB±1dB内,且回波损耗>15dB,隔离度>20dB。2.为提升耦合结构的回波损耗和隔离性能,研制了加载锯齿形结构的2~8GHz90°混合耦合器,并制作了加载矩形结构的6~18GHz 90°混合耦合器。实测结果表明:2~8GHz的耦合器具有回波损耗>20dB,隔离度>25dB的性能;6~18GHz的耦合器具有回波损耗>15dB,隔离度>17dB的性能。3.从切比雪夫(Chebyshev)变换器和隔离电阻两方面对宽带功分器的本质进行了研究。描述了2~8GHz、6~18GHz器件的设计方法,进行了模型仿真,并制作了2~8GHz的等分同相功分器。4.利用90°混合耦合器的设计原理,研制了部分、完全两种集成方式的2~8GHz六端口电路,并研制了完全集成方式的6~18GHz六端口电路。搭建了测试系统,对模块进行了验证测试,结果表明:与Agilent E8363B测试结果相比较,幅度误差小于1.2dB,相位误差小于10°。更多还原

【Abstract】 As a kind of vacuum device work in the large-signal microwave status,travelling-wave-tube amplifier(TWTA) with excellent performance wideband, high gain and high operating frequency, etc., are widely used in the field of deep space radio communications and electronic countermeasures to detect, and which plays an important role in the signal amplification. Since TWTA is a non-linear device, under large signal conditions it will exhibit nonlinear amplitude and phase(AM-AM, AM-PM) effects which will affect the whole system lead to bad communication quality. Based on this, it is necessary to create a pre-test module for TWTA’s AM-AM, AM-PM effects.Based on the basic principles of TWTA test, first, this paper survey the research status on non-linear amplitude and phase of the TWTA both here and abroad. Through in-depth understanding of both the amplitude and phase of the testing system, taking fabricating cost, on-line testing and test precision into account, here proposes the use of amplitude and phase tests based on six-port circuit. The derivation of the amplitude correlation coefficient, confirmed the test module using six-port circuit as a non-linear amplitude and phase components is rational. This article studied and tested module design from the following aspects:1. Based on the test philosophy, determined using multi-section coupler with asymmetric form as sampling device. Doing a research on multi-section symmetric/asymmetric coupler,and a modified 10 dB coupler with coupling about 10±1dB, return loss >15dB, isolation >20dB has been made out.2. In order to improve return loss and isolation performance, 2~8GHz 90° hybrid coupler with zigzag structure has been made out, and a 6~18GHz 90° hybrid coupler with rectangular structures has been designed. The measured results show that: 2~8GHz 90° hybrid coupler possessed a performance of return loss >20dB, isolation >25dB; 6~18GHz 90° hybrid coupler had a performance of return loss >15dB, isolation >17dB3. Researching the innate characters of the ultra-wide-band Wilkinson power divider, which including chebyshev transformer and isolation resistors. And given the methods to design power dividers worked in 2~8GHz and 6~18GHz frequency,and simulation procedure have been carried out to the power dividers. The physical of the power divider worked in the frequency 2~8GHz have been made out;4. Based on the design principle of 90° hybrid coupler, semi- and fully- integrated forms of six-port circuits worked in 2~8GHz have been designed, and a fully- integrated form 6~18GHz six-port has been developed. A test system has been set up to verify the feasibility of the module. Compared with Agilent E8363 B measured scores, the test results show that: amplitude error less than 1.2dB, phase error less than 10°.更多还原