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类型 应用研究 预答辩日期 2017-11-21
开始(开题)日期 2013-11-29 论文结束日期 2017-09-21
地点 李文正楼六楼大会议室 论文选题来源 其他项目    论文字数 7 (万字)
题目 短毫米波宽带射频前端理论与关键技术研究
主题词 W/D波段,接收机噪声系数,下变频器,射频前端,混频器
摘要 随着超高速数据传输和高分辨率雷达成像技术的迅速发展,微波毫米波系统工作带宽要求越来越高,W波段、D波段等短毫米波段频谱资源开发利用备受关注,相关的宽带射频前端理论与关键技术研究已成为富有挑战性的前沿课题。本文以实现短毫米波段宽带高性能射频前端为目标,针对目前宽带射频系统研究开发中普遍存在的若干理论与技术问题,在短毫米波宽带接收机噪声系数理论与精确测量方法、W波段低杂散射频前端系统方案、W波段宽带低噪声下变频器与接收组件的设计与实现技术、W波段宽带收发前端原理样机研制以及D波段宽带谐波混频器研制等方面进行了深入研究。本文主要研究进展包括: 1、建立了宽带非平衡信频/镜频通道接收机的双边带、单边带噪声系数理论模型,将传统的理想超外差接收机噪声系数理论公式推广到了非理想宽带接收机情况,深入研究了通道不平衡度对接收机噪声系数的影响,提出了相应的设计准则。基于传统的测量噪声系数的Y因子法和直接测量法,提出了适用于非平衡信频/镜频通道接收机噪声系数的精确测量方法,并通过构建三种W波段超外差接收机测量系统进行了实验验证。结果表明,通过Y因子法和直接测量法测得的噪声系数均与推广的理论模型相符合。将宽带非平衡信频/镜频通道接收机噪声系数理论应用于高性能W波段宽带下变频器和宽带接收组件的指标分配及硬件研制。 2、提出了将高增益低噪放芯片和基于反向并联二极管对结构的谐波混频器一体化集成优化的下变频器设计方案,采用级间网络匹配技术结合三维电磁仿真方法,解决了超宽带W波段低噪放与二次谐波混频电路增益平坦度优化的技术难题,实现了在89~101GHz范围内,变频增益波动优于±1.5dB、双边带噪声系数3.0~5.0dB的优良技术指标。提出了一种带有耦合检波式自保护电路的宽带接收组件设计方案。通过建立检波二极管宽带等效电路模型,完成了宽带、低损耗的W波段耦合检波式自保护电路的准确设计。在75~80GHz范围内,所研制的宽带接收组件变频增益大于11dB,增益波动在±1.6dB以内,镜频抑制度远大于40dB,技术指标均满足雷达整机系统研制的要求。 3、针对W波段宽带FMCW探测雷达具体应用需求,提出了将双本振架构和二次变频接收相结合的W波段宽带射频前端系统技术方案。基于相互独立的异频收发本振源,建立了系统分析模型,深入分析了系统各节点信号频谱分布及其相位噪声特性,提出采用双本振架构与二次变频接收相结合的系统总体结构,从原理上阐述了该总体方案实现相噪对消的可行性。在此基础上,完成了系统关键指标的参数论证,并充分考虑各级有源器件和混频倍频模块的电性能参数,合理分配了各级电路功率,对其中存在的谐杂波频谱及其滤除方法进行了深入分析,改善系统杂散抑制度,建立了低杂散W波段宽带射频前端系统方案。 4、提出了一种新型的紧凑型平面微带低通滤波器电路,将中频低通滤波器的阻带高频端拓展到40GHz,有效改善了二次变频接收机中频信号的频谱纯度。该滤波器中心区域由相互交叉耦合的三种扇形谐振器、两种四分之一圆形谐振器和一系列高阻抗线组成,形成了2.3-10GHz的较宽阻带和高滚降速率。通过增加三类加载半圆形贴片的高阻抗线谐振器和一类折叠型阶跃阻抗线谐振器,在Ka频段产生了多个传输零点,从而将阻带拓宽到18次谐波频点以上。实测结果表明,所研制的中频低通滤波器阻带覆盖范围宽达2.2~40GHz,抑制度优于25dB,滚降速率达到104dB/GHz,与已报道的国内外同类滤波器相比,阻带带宽和滾降速率综合性能具有明显优势。 5、在W波段宽带射频前端系统研制中,将场路结合的一体化仿真方法应用于W波段二路合成三倍频器的优化设计,并提出了在本振链路和中频端联合应用高阻带抑制度带通/低通滤波器的杂散抑制方案,解决了宽带射频前端系统带内平坦度优化、杂散抑制等关键技术问题。对W波段功率合成三倍频器的二极管匹配电路、输入功分网络、输出合成网路进行联合仿真优化,实现了在10GHz带宽范围内优于±0.8dB的输出功率平坦度。通过对金丝键合方式及其损耗特性的试验研究,解决了接收本振信号在高端频点功率偏低的问题,改善了增益的平坦度。通过在本振链路和中频端同时配置具有高阻带抑制特性的滤波器,大幅减少了接收链路的谐杂波分量。将收发链路、本振链路射频模块集成联调,完成了W波段宽带射频前端系统的研制。实验结果表明,在10GHz带宽范围内,射频前端发射输出功率为9.5dBm±1.0dB,接收增益波动在±1.8dB以内,双边带噪声系数为3.7~5.1dB,收发系统整体杂散抑制度大于50dBc,整体闭环测试验证了系统结构的相噪抵消效果,可直接应用于W波段短距离探测系统。 6、提出了利用串联双肖特基结二极管的单结工作模式实现D波段二次谐波混频器的技术方案,建立了单结工作模式下包含无源寄生效应的二极管宽带等效电路模型。将该模型和负载牵引技术相结合,快速获得射频端和本振端的最佳阻抗特性,进而优化整体电路尺寸,获得优良的变频损耗宽带频响特性。研制成功了低成本、高性能的D波段宽带二次谐波混频器,测试表明,在135~165GHz范围内,混频器单边带变频损耗为14±3dB,在140~160GHz范围内变频损耗为12±1dB,中频带宽覆盖0~20GHz,实验结果验证了二极管单结等效电路模型的准确性以及设计方法的有效性。提出了一种对称型的高Q值H面扩展陷波腔结构,对陷波腔谐振机理进行了深入分析,成功应用于具有阻带增强特性的D波段全波段波导带通滤波器的研制。在106~174GHz范围内,滤波器实测插损典型值为1.2dB,在180GHz处抑制度超过30dB,主要性能指标与国外同类产品相当。所研制的高性能谐波混频器和带通滤波器为D波段宽带接收机的研究打下了重要基础。
英文题目 Research on theory and techniques of broadband RF frontend at short-millimeter wave bands
英文主题词 W/D band, receiver noise figure, downconverter, RF frontend, mixer
英文摘要 At microwave and millimeterwave bands, demand for wide system bandwidth is increasing along with the remarkable progress in high-rate data-transfer and high-resolution imaging techniques. Therefore, development and utilization of spectrum resources at W/D band are attracting extensive attention. Theory and critical techniques of broadband components and RF frontend have become challenging and frontier research projects. The objective of this work is to develop broadband high-performance RF-frontend system at short-millimetre wave bands. Relevant theory and key techniques in the development are analyzed and studied in depth. Progress has been made in many aspects, including theory and precise measurement of receiver noise figure, system scheme design of low-spurious W-band RF frontend, development of W-band broadband downconverter and receiving module, development of W-band RF-frontend prototype, and D-band broadband sub-harmonic mixer (SHM). The main progresses of this dissertation are as follows: 1、Double-side-band noise figure (DSB NF) and single-side-band noise figure (SSB NF) of a broadband receiver with unbalanced signal/image-frequency channels are theoretically modelled. The conventional NF formulas of ideal heterodyne receivers are extended to those of the non-ideal receivers. The influences of the unbalances between the signal/image-frequency channels on the NF are studied in depth. The design guidelines for non-ideal receivers are deduced. Accurate NF measurement methods are proposed for receivers with unbalanced signal/image-frequency channels based on the traditional Y-factor method and direct-measurement method. Experiments have been carried out by establishing three types of W-band heterodyne receivers. The measured results of NF by Y-factor method and direct-measurement method are in agreement with those predicted by the theoretical NF model. The theoretical NF model of receivers with unbalanced signal/image-frequency channels is applied to assign appropriate specifications. Prototype of broadband W-band downconverter and receiver module with high-performance have been developed. 2、A novel circuit design scheme is proposed for W-band broadband downconvertoer, in which a high-gain low-noise amplifier (LNA) MMIC die is integrated with a sub-harmonic mixer (SHM) based on anti-parrallel diode pair (APDP) as a whole circuit module. The interstage matching techniques and the 3D electro-magnetic (EM) simulation method are applied to improve the gain flatness of ultra-wideband LNAs and mixers. The measured gain fluctuation of the W-band downconverter is within ±1.5dB over 89~101GHz, and the DSB NF is 3.0~5.0dB. A broadband W-band receiver module with coupled-detector self-protection circuit is proposed. The coupled-detector self-protection circuit at W band with low loss and wide bandwidth is accurately designed based on the established broadband equivalent circuit model of the detector diode. Measured gain of the developed W-band receiver module is higher than 11dB with fluctuation within ±1.6dB. The image-frequency rejection is higher than 40dB. The technical indexes meet the requirements of the radar application system. 3、A system design scheme of W-band RF frontend is proposed based on dual local-oscialltor (LO) architecture in combination with two-stage down-conversion receiver design, according to the demands of broadband FMCW detection radar application systems. The theoretical model of the system is established based on a dual LO source with two different output frequencies for receiver and transceiver, respectively. The beat signal property and its phase noise are analyzed in depth. The system overall structure based on dual-LO architecture in combination with two-stage down-conversion receiver design is proposed. Feasibility of phase noise cancellation based on this overall structure is theoretically validated. On this basis, key technical indexes of the RF frontend are determined. Harmonic and spurious spectrums are analyzed in the cascaded active components, mixers and multipliers, while the suppression level and filtering method are provided to improve the spur suppression performance. 4、A novel compact microstrip lowpass filter (LPF) with ultra-wide stopband up to 40 GHz is proposed, which effectively improves the spectrum purity of the IF signal. The central part of the LPF consists of three basic circular sectors, two smaller quadrants and a number of high impedance lines that are cross-coupled to form a high cut-off rate and a moderate stop band from 2.3-10 GHz. Then, four types of resonator cells (RCs), three of which are high impedance lines loaded with semi-circulars and one of which comprises folded step-impedance lines, are added to the central part to generate additional transmission zeroes up into Ka band. As a result, an ultra-wide stopband with 18th-harmonic suppression has been attained. A demonstration filter with 3 dB cutoff frequency of 1.96 GHz has been designed and fabricated. The measured stopband bandwidth of the LPF is from 2.2GHz to 40GHz with suppression level greater than 25 dB, and the roll-off rate is 104 dB/GHz. Its roll-off rate is better than the reported similar LPFs. 5、In development of the broadband W-band RF-frontend system, the combined circuit- field simulation method is applied to the optimization of the W-band two-way power-combined frequency tripler, and the system design scheme for high spur suppression is proposed which employs bandpass filter (BPF)/LPF with high stopband suppression in the LO chain and IF port of the receiver. In this way, the key technical proplems are solved, including the optimization of gain/amplitude flatness and the spur rejection over wide bandwidth. To improve the output power at higher frequencies, the matching networks of the diodes are modelled together with the input power divider and the output power combiner in simulated and optimized. The fluctuation of the W-band output power is better than ±0.8dB over the 10GHz bandwidth. The broadband loss performances of bonding wire are tested by experiment in actual circumstance. The technical problem that the LO power decreases at higher frequencies in band is solved and the conversion-gain flatness of receiver is improved. In addition, harmonics and spurs are greatly suppressed by adding high-performance filters in LO and IF circuits. The broadband W-band RF-frontend system is developed by assembly and test of the transceiver and LO chains. Measured W-band output power is 9.5dBm±1.0dB over 10GHz bandwidth, and fluctuation of the receiver gain is within ±1.8dB. The DSB NF is 3.7~5.1dB. The spur suppression is greater than 50dBc of the system. Phase noise cancellation is validated in the RF frontend closed-loop experiments, constructed by the transmitter and the receiver together. The RF frontend is practical and available for W-band short-range detection radar systems. 6、A circuit scheme for implementation of D-band SHM is proposed based on the single-junction operation of a dual-junction Schottky diode chip. Broadband single-junction equivalent circuit model of the diode chip is developed, considering the parasitic effects. The load-pull method is employed in combination with the established diode model. In this way, impedance characteristics at RF and LO ports corresponding to optimum conversion loss can be obtained effectively, and the circuit size are optimized according to the impedances. The measured SSB conversion loss (CL) is 14±3dB over 135~165GHz,and 12±1dB over 140~160GHz. The IF frequency band covers 0~20GHz. The broadband single-junction equivalent circuit model of the dual-junction diode chip is validated and the effectiveness of the design method are verified. A symmetrical high-Q H-plane notch cavity structure is proposed and its resonance mechanism is analyzed. It is successfully applied to the development of D-band fullband waveguide BPF with enhanced stopband performance. The measured insertion loss is typically 1.2dB over 106~174GHz, and the suppression is greater than 30dB at 180GHz. The main technical indexes are comparable to similar foreign commercial products. Development of the low-cost and high-performance SHM and BPF provide an essential foundation for research on broadband D band receivers.
学术讨论
主办单位时间地点报告人报告主题
东南大学 2011.06.30 东南大学李文正楼北614 常若艇 无线电频谱及卫星轨道资源管理框架
东南大学 2011.11.23 东南大学李文正楼南409 陈志南 60/140GHz毫米波基板集成天线
东南大学 2011.12.22 东南大学李文正楼北614 杨帆 新一代高增益天线
东南大学 2012.03.19 东南大学李文正楼北614 Maged Elkashlan Cooperative Networks:Theory, Principles, and Protocols
东南大学 2012.03.25 东南大学李文正楼中620 蒋姝 平行耦合微带滤波器设计方法研究
东南大学 2014.04.02 东南大学李文正楼中620 蒋姝 V波段二次谐波混频器研究
东南大学 2014.05.10 东南大学李文正楼中620 蒋姝 V波段宽中频正交混频器研究
东南大学 2014.07.09 东南大学李文正楼中620 蒋姝 W波段正交混频器研究
     
学术会议
会议名称时间地点本人报告本人报告题目
IEEE International Conference on Microwave and Millimeter Wave Technology 2016.06.05 北京国际会议中心 A 5–19GHz amplitude-shaped power amplifier using microstrip SIRs loaded with film resistors
Asia-pacific Microwave Conference 2015.12.06 南京金陵饭店会议中心 A novel 30–40 GHz bandpass filter with sharp rejection using symmetrical notch cavity
     
代表作
论文名称
Compact microstrip lowpass filter with ultra-wide stopband based on dual-plane structure
Sharp roll-off planar lowpass filter with ultra-wide stopband up to 40 GHz
A 5–19GHz amplitude-shaped power amplifier using microstrip SIRs loaded with film resistors
 
答辩委员会组成信息
姓名职称导师类别工作单位是否主席备注
陈彬 正高 教授 博导 解放军理工大学
吴文 正高 教授 博导 南京理工大学
潘明海 正高 教授 博导 南京航空航天大学
薄亚明 正高 教授 博导 南京邮电大学
朱晓维 正高 教授 博导 东南大学
      
答辩秘书信息
姓名职称工作单位备注
王文博 其他 讲师 东南大学