A grounded coplanar waveguide technique for microwave measurement of complex permittivity and permeability

We present a method for extracting the complex permittivity and permeability of dielectric/magnetic thin films in a grounded coplanar waveguide configuration. The technique is applicable for extraction of these material parameters for lossy and lossless materials over a broad frequency range with high accuracy. For validation, we extracted complex permittivity and permeability, using the scattering parameters obtained from the full-wave electromagnetic simulation for two test cases over a frequency range of 5 to 15 GHz. Accuracy for both dielectric as well as magnetic materials is within 2% error.

I. Introduction

With applications trending in the direction of higher operating frequencies, substrate material characteristics need to be taken into much consideration. Methods for extracting complex permittivity and permeability, originally purposed by Weir [1] and Barry [2], allow measurements of complex permittivity and permeability over broadband frequencies. Methods based on this work have been derived for many different structures. Previously, work by [3]–[9] have demonstrated broadband extraction using stripline, microstrip, and waveguide methods. The method purposed in this letter will simultaneously extract complex permittivity and permeability of thin films using a grounded coplanar waveguide (GCPWG) configuration with high degree of accuracy. Complex permittivity and permeability can be extracted from the simulated/measured S-parameters. Conformal mapping techniques are used to isolate the material characteristics of the known substrate from those of the unknown material.