Research On The Impedance Characteristics Of Printed Passive Electronic Components

Miniaturization and integration of electronic equipment demand increasingly with the development of science and technology,printed electronics technology provides a new idea to solve this problem,it replaces the resistors,capacitors and inductors on traditional scircuit boardsand by putting the passive electronic components into planar structure,printing method not only reduces manufacturing costs,but also reduces the size of the equipment.In this thesis,the interdigital capacitor and planar spiral inductor passive electronic components on flexible PET substrate are produced by screen printing,measured their impedance characteristics in the range from 100 to 600MHz.and researched the design method,printing process and impedance characteristics analysis about two kinds of passive electronic components.In order to achieve low-cost impedance measurement,making a simple impedance meter by AD8302 chip and dual directional coupler.The numerical simulation and theoretical analysis prove the design method of passive electronic components.Numerical simulation establishes interdigital capacitor model on ceramic substrate and planar spiral inductor model on FR4 substrate with Ansoft's HFSS software,receiving their impedance measurement values during the frequency from 100 to 600MHz.Theoretical analysis establishes high-frequency equivalent circuit model which is the same with simulated structure and calculates circuit parameters,then determines impedance characteristics with these parameters.Finally making the physical structure of interdigital capacitor and planar spiral inductor,and measuring their impedance characteristics with the E4991A impedance analyzer.The results show that the simulation result,the circuit model calculation results and the actual test results remained the same basically,verifing the validity of the design method.This thesis determines appropriate process parameters and printing inks by analyzing the screen printing process parameters(screen mesh,substrate material,ink concentration and printing times)affected printing film resistance and different kinds of ink affected the impedance characteristics of printing interdigital capacitor.Printing interdigital capacitors and planar spiral inductors with different structural parameters on PET substrate,and analyzing different structural parameters(the finger length,finger width,gap width,finger numbers and conductor thickness of interdigital capacitor,the coil width,gap width,conductor thickness and coil turns of planar spiral inductor)affected their impedance characteristics during the frequency from 100 to 600MHz.then comparing measurement results of interdigital capacitors and planar spiral inductors printed by silver ink and the simulation results by metallic silver conductor,the two curves coincide substantially,it shows that the printed electronic components have good impedance characteristics in this band.This thesis builds a load impedance measurement system with amplitude and phase detection circuit by AD8302 chips and dual directional coupler,then measures 51 Ω and 100Ωtwo kinds of chip resistors during the frequency from 70 to 110MHz,receives test load impedance values by measuring the reflection coefficient,and compares the test results with the measurement results of Agilent E4991A impedance analyzer,the resouts show that:the real part maximum and minimum of 51Ω are 49.98Ω and 48.5Ω during the entire frequency range,the relative error of maximum and minimum are 2.1%and 0.6%,the maximum value of the imaginary part measured 3.6Ω,the minimum is 2.5Ω,it exhibits inductance characteristics;the real part maximum and minimum of 100Ω are 99.85Ω and 96.79Ω,the relative error of maximum and minimum are 3.3%and 0.9%,the minimum value of the imaginary part measured is-8.3Ω,the maximum value is-3.24Ω,it exhibits capacitance characteristics.The simple impedance meter realizes impedance measurement in the higher frequency range initially.