Grounded coplanar waveguide-based 0.5–50 GHz sensor for dielectric spectroscopy

There is a need for accurate knowledge of complex permittivity of biosystems for development of electromagnetic diagnostic and therapeutic methods. However, standard open-ended coaxial probe method for measurement of complex permittivity requires rather large sample volumes which is prohibitive for analysis of many types precious biomolecules available only in small volumes. To help to alleviate this issue, we have designed, fabricated and tested a novel grounded coplanar waveguide-based sensor for dielectric spectroscopy of small volumes for the 0.5–50 GHz band. Our method (i) enables 20-fold lower sample volumes than the standard open-end coaxial probe method, (ii) does not require a reference liquid to obtain absolute values of complex permittivity, (iii) is microfluidics-free and the whole sensor can be fabricated by standard printed circuit board techniques. We believe that our sensor and method contributes to low-cost broad band acquisition of complex permittivity data of biomaterials and biomolecules which can be used for development of new therapeutic and diagnostic methods.