Research On Bending Characteristics Of RF MEMS Flexible Devices With Typical Membrane/beam Structure

In the current wave of information development,flexible electronic devices,with unique flexibility,ductility,high efficiency and low cost manufacturing process,have very broad application prospects in the fields of national defense,information,medical treatment,energy and other fields,and have unparalleled importance and advantages in conformal,miniaturization,lightweight and intelligent applications in complex environment.MEMS(Micro Electro Mechanical Systems)flexible devices,such as conformal,high performance,small volume,intelligent sensors and actuators,become an indispensable part of flexible electronic systems.In particular,RF MEMS flexible devices,due to their wide application prospects in airborne,spaceborne radar and IoT communication systems,make various RF MEMS flexible actuators and sensors a research hotspot in recent years.At present,the main research contents and objectives of RF MEMS flexible devices are still in the stage of device design,fabrication and performance testing under flat conditions.The research on bending characteristic modeling with experimental characterization is still vacant.However,it is urgent to establish a bending characteristic modeling of RF MEMS devices based on flexible substrate from both scientific research and engineering application perspectives,so as to promote the further research and application.In this paper,the bending characteristic modeling of typical RF MEMS flexible devices with membrane/beam structure is established,and the effect of flexible substrate bending on the mechanical,microwave and dynamic characteristics of flexible devices with typical membrane/beam structure in complex environment applications is explored.After investigating and analyzing the research background,application fields and development status of RF MEMS flexible devices,the following research work is carried out:(1)A modeling of the bending characteristics on typical MEMS membrane/beam structures was established.By analyzing the basic theory of MEMS driver design,the working principle,mechanical characteristics,microwave characteristics and dynamic characteristics of double-end fixed/cantilever beam electrostatic actuator and V-beam thermal actuator are given.The theoretical analysis of the effect of bending flexible substrate on the parameters is also carried out.(2)Based on the modeling of bending characteristics,combined with the process limitations,the size and structure of the typical MEMS membrane/beam structures is finally determined,including the double-end fixed beam electrostatic actuator,the cantilever beam electrostatic actuator and the V-beam thermal actuator,and the actuation voltage/current,return loss and actuation time under different curvature of bending flexible substrate are simulated.The simulation results are consistent with the theoretical calculation results.(3)Three typical MEMS membrane/beam structures were fabricated.The actual size of devices was determined,and the performance parameters were measured based on the bending test stands with different curvatures.The experimental results show that although the air gap of double-end fixed beam structure and cantilever beam structure is too thick for actuation,the experimental results of microwave performance are basically conforms to the theoretical calculation results.And the experimental results of the V-beam structure show that mechanical and dynamic characteristics are in agreement with the theoretical calculation results under the actual size.In this paper,the bending characteristics modeling of RF MEMS flexible device based ontypical MEMS membrane/beam structure is established for the first time.The influence of flexible substrate bending on the performance is analyzed,and the variation law of mechanical,microwave and dynamic characteristics are obtained.The research fills the gap of the bending characteristic modeling of RF MEMS flexible devices at home and abroad,and provides a theoretical basis for the practical research and application of RF MEMS flexible devices in complex environmental applications.