Study Of Radio-frequency Characteristics Of Flexible Passive Devices And Interconnects

High-speed flexible electronics have received lots of attention for their unique advantages such as light-weight,bendability,mechanical stability,low cost and so on.And flexible microwave TFTs,flexible microwave PIN diodes and switches have been realized based on semiconductor nanomembranes,which indicates the possibility of flexible monolithic microwave integrated circuits based on plastic substrates.Besides,high-performance flexible passive devices such as inductors,capacitors and interconnects are also indispensable for the realization of high-speed flexible integrated systems.The study of radio-frequency characteristics of flexible passive devices is critical and important.Firstly,according to the basic electrical theory,this paper introduces the layout parameters and process parameters,and makes a detailed analysis of the equivalent model,loss mechanisms and performance indexes.A full-wave electromagnetic(EM)simulator HFSS is used to accurately characterize spiral inductors on a plastic substrate.Studies of the performance of spiral inductors on a plastic substrate have been carried out so as to shed light on the roles of layout and process parameters.It proves that the spiral inductor on a plastic substrate exhibits better performance compared to the one on conventional silicon substrates.The improved equivalent circuit model of flexible spiral inductors is proposed,and this paper discusses and analyzes the performance of spiral inductors under bending states.The layout design of flexible spiral inductors is completed by using a software CleWin.Then this paper introduces the structure of flexible MIM capacitors and parameters of the process.The classical equivalent circuit model is introduced and the performance indexes of flexible capacitors are analyzed.The paper focuses on the research of improving performance of flexible capacitors using HFSS software.The performance of flexible capacitors under bending states is analyzed and discussed.And this paper completes the layout design of flexible layout MIM capacitors with different dimensions.Finally,the radio-frequency characteristics of flexible interconnects are analyzed and discussed.This paper introduces the basic structure and distribution model as well as formulas of performance factors of CPW(coplanar waveguide).This paper focuses on the influence of different flexible substrate structures on the loss characteristics of flexible CPW.The CPW on PET/SU-8 substrate shows the minimum loss.And the performance of CPW on flexible substrates is compared with that on conventional Si substrate.The layout design of flexible interconnects with different sizes on different substrates is completed.