Investigation Of Dual Stripline Resonators Method For PCB/PWB Dielectric Properties Measurements

The study of dielectric properties of materials is the basis of the electronic devices and systems.The permittivity is one of most important factors especially in the design,simulation and production stage of high frequency/speed PCB.In general,the dielectric properties of commercial PCB materials are measured at lower frequencies(e.g.,100 MHz and 1GHz).With the development of modem microwave and digital system,the density of interconnection is becoming higher and higher,the quantity of embedded components PCB is creasing,data rate is faster and faster.The influence of dielectric properties of the substrate on the signal interconnection becomes more and more important and obvious,measurement frequency required for PCB dielec trics are higher and higher.It's significance to know exactly the complex permittivity of PCB dielectrics,whether it is for material manufacturers,or designer,PCB fabricator.In this paper,an innovative method dual strip line resonators for the permittivity of printed circuit board substrate in frequency range of 1 GHz to 10 GHz was improved and introduced,which is suitable for R&D and manufacturing control.According to the method,a half and full wavelength strip line resonators are fabricated on a printed circuit board.Resonant characteristic curves of resonators with different lengths are measured by a vector network analyzer(VNA),resonant frequencies and quality factors in a wide frequency range(1GHz to 10GHz)are obtained,the effective electrical length increment of the resonators is further corrected according to an algorithm,and finally the relative dielectric constant and the dielectric loss tangent of the two laminated PCB dielectrics are measured by this method.This paper is divided into five chapters.In the first chapter,the dielectric and its properties,the structures of PCB,as well as various testing methods for dielectric properties of PCB media in current industry were reviewed.In the second chapter,starting from the circuit model of strip transmiss ion line,though the research on the structure and properties of stripline resonator,a dual stripline resonators method for dielectric measurement of PCB laminated material is proposed and simulated by HFSS to get design concerns and measurement procedure.In the third chapter,test coupon was designed and properties of two PCB materials were tested according to previous chapter.The method discussed in this paper is realized.In the fourth chapter,the usability of the method was analyzed according to the engineering requirements.In the fifth chapter,whole work was summarized,and the advantages and disadvantages of dual resonators method,the future optimization direction of this method were elaborated.