摘要
本文提出一种基于GaAs MMIC技术的Ka波段MEMS定向耦合器结构,并基于微波网络理论对其建立集总S参数模型,从而实现超宽频带的耦合应用。该耦合器在结构上采用全共面传输线形式以易串并联其他元器件,并采用MEMS空气桥以实现地线互连,而无需片外键合线。在模型上,首先对MEMS共面定向耦合器进行各部件结构划分,并提取出相应等效电路模型,其次利用微波级联理论对各部件进行级联,可解出其整体的S参数。利用该模型分析与优化耦合器的关键尺寸参数,优化后MEMS共面定向耦合器在Ka波段S_(11)小于-20 dB、S_(21)在-0.84 dB~-0.89 dB之间、S_(31)在-10.5 dB~-11.3 dB之间、S41小于-25 dB。利用HFSS软件对在该尺寸结构下定向耦合器进行仿真,在Ka波段其S_(11)小于-25 dB、S_(21)在-0.70 dB~-0.79 dB之间、S_(31)在-9.4 dB~-11.5 dB之间、S_(41)小于-25 dB。通过比较发现数学解析模型和HFSS仿真结果显示了较好的吻合,在Ka波段中心频率处S参数误差小于20%,从而验证了解析模型的合理性和有效性。此外,该Ka波段MEMS定向耦合器的设计和模型可作为研究该类MEMS器件的参考。
This paper presents a Ka-band MEMS directional coupler based on the GaAs MMIC technology and establishes a lumped S-parameter model based on microwave network theory to realize ultra-wideband coupling applications.In the structure,this coupler adopts the form of fully coplanar transmission lines for easily connecting other components in series and parallel.Two MEMS air bridges are used for achieving the interconnection of the ground lines without the need of off-chip bonding wires.In the model,the MEMS coplanar directional coupler is firstly divided into several components.The corresponding equivalent circuit model is extracted,and finally the components are cascaded using the microwave lumped theory to solve the overall S-parameter model.Using the model,some key size parameters of this coupler are analyzed and optimized,and the MEMS directional coupler after optimization demonstrates that the S_(11) is less than -20 dB,S_(21) is between -0.84 dB~-0.89 dB,S_(31) is between -10.5 dB~-11.3 dB and S_(41) is less than -25 dB in the Ka-band.The directional coupler is simulated by HFSS under the obtained size,and the simulation results show that the S_(11) is less than -25 dB,S_(21) is between -0.7 dB~-0.79 dB,S_(31) is between -9.4 dB~-11.5 dB and S_(41) is less than -25 dB.By compassion,the mathematical analysis model and the HFSS simulation results show good agreement,and the errors of S-parameter are less than 20% at the center frequency,which verified the rationality and effectiveness of the analytical model.In addition,the design and model of this Ka-band MEMS directional coupler can be used as a reference for studying the MEMS devices of similar type.
作者
刘佳琦
张志强
黄晓东
LIU Jiaqi;ZHANG Zhiqiang;HUANG Xiaodong(Key Laboratory of MEMS of the Ministry of Education,Southeast University,Nanjing Jiangsu 210096,CAina)
出处
《传感技术学报》
CAS
CSCD
北大核心
2021年第3期285-290,共6页
Chinese Journal of Sensors and Actuators
基金
国家自然科学基金项目(61604039)
至善青年学者支持计划项目(2242019R40030)。
