US EPA

2188690 

Journal Article 

A method for determining the dielectric constant of microwave PCB substrates 

Yamacli, S; Ozdemir, C; Akdagli, Ali 

2008 

Yes 

International Journal of Infrared and Millimeter Waves
ISSN: 0195-9271
EISSN: 1572-9559 

29 

2 

207-216 

10.1007/s10762-007-9317-6 

WOS:000252157000010 

This paper presents a simple method for determining the dielectric constant of microwave PCB substrates. In the presented method, a bandpass microstrip filter designed on the PCB substrate with a user-predicted dielectric constant value is implemented for a given center frequency. The simulation results of the designed bandpass filter are obtained by the help of microwave design software; XFDTD (R). Experimental results regarding the filter frequency characteristic are accomplished by means of a vector network analyzer. The simulation results of the designed filter are modified to overlap with the experimental ones by varying the dielectric constant value. When the simulation and experimental results are overlapped, the value of dielectric constant is accurately selected. In order to illustrate the validity of proposed method, the dielectric constant values of flame resistant-4 (FR4) substrates are acquired at IEEE 802.11b/g and IEEE 802.11a wireless local area network (WLAN) application frequencies. The results obtained by using the presented method agree with the previous studies in the literature. 

dielectric constant; PCB substrate; microstrip filter; FR4