Numerical modeling of two microwave sensors for biomedical applications

Abstract

The purpose of this invited paper is to give readers a critical and comprehensive overview on how to extract dielectric properties of a bioliquid within a broad frequency range. Two sensors are used in the paper to characterize saline solutions by measuring the broadband complex permittivity. The two sensors are based on transmission line and interdigital electrodes designed for low-and high-frequency measurements, respectively, on the basis of the coplanar waveguide structure due to its convenience of fabrication and integration with microfluidic structures for liquid measurements. Different from traditional work where the finite element simulation method is used, the characterization theories of the two sensors are built based on a numerical modeling procedure, which can dramatically increase the device design efficiency, taking just a few seconds. Differently from the finite element method, the proposed numerical analysis utilizes a conformal mapping technique for both sensors. The characterization theories of the two sensors are validated by measuring de-ionized water. The platform is finally used to measure 0.1 and 0.5 mol/L saline solutions within a broadband frequency range going from 10 up to 50 GHz, with the repeatability error within 5%.

Inkjet-Printed Interdigitated Capacitors for Sensing Applications: Temperature-Dependent Electrical Characterization at Cryogenic Temperatures down to 20 K

“…The small size of IDCs makes them suitable for sensing applications and integration into microfluidic devices. In microfluidic systems, IDCs can be used as sensing elements to monitor the conductivity of the liquid under test or its dielectric properties, detecting and quantifying chemical and biological species [21,22,27,28]. These features make IDCs suitable for medical diagnostics and lab-on-a-chip applications [8,29].…”

Measurement of low‐loss aqueous solutions permittivity with high detection accuracy by a contact and free‐label resonance microwave sensor

“…One of the reasons for the ease of checking the sensor is that only the resonance in one of the scattering parameters is explored to check the sensitivity, and this issue does not involve the researcher in other parameters, especially the phase. The proposed sensor with the features defined for it can be used in the field of biomedical, 56 and microfluidic 57 sensors can create very high sensitivity by creating LC resonators, [53][54][55] and medical industries can use it in these fields.…”

Electrical Characterization of Through-Silicon-via-Based Coaxial Line for High-Frequency 3D Integration (Invited Paper)

“…A theory related to the coaxial-like TSV is further derived, providing some guiding suggestions for the practical manufacturing process. The characteristic impedance of these TSV-based coaxial lines is mainly studied using the conformal mapping method [25][26][27][28] and validated using the finite element method (FEM) simulations, which provide an accurate description of the considered microwave structure [28][29][30][31].…”