Wide bandwidth measurement of complex permittivity of liquids using coplanar lines

Planar Microwave Sensors for Complex Permittivity Characterization of Materials and Their Applications

“…However, in the case of liquids and semi-solids, it is easier to have the sample as a superstrate. There have been many investigations into the use of planar circuits for complex permittivity measurements of liquids (Stuchly, 1998, Raj, 2001, Facer, 2001, Queffelec, 1994, Hinojosa, 2001, Chen, 2004 Figures 5 and 6 show typical planar cells for dielectric permittivity measurements of liquid materials. The liquid to be measured completely covers the planar circuit and is enclosed inside a low loss container which is fixed firmly or epoxied on top of the board.…”

Integrated On-Chip THz Sensors for Fluidic Systems Fabricated Using Flexible Polyimide Films

“…To date, the on-chip systems that have been used for the study of bulk fluid samples in the THz regime use either microstrip line (MSL) [7] or planar Goubau line (PGL) [8,9] geometries, whilst coplanar waveguides (CPWs) have been used at lower frequencies (1 Ð 5 GHz) [10]. In each of these systems, the evanescent electric field propagating along the waveguide can be employed for the analysis of overlaid dielectric materials, by observing changes induced by proximal samples in the transmission of pulses over the length of the waveguide, such as the attenuation or the propagation velocity.…”

Development of planar Goubau line - microfluidic integrated devices for THz spectroscopy of liquid analytes

“…Two types of transmission line have been used for on-chip microfluidic spectroscopy in the frequency range of interest; microstrip lines (MSLs) [2] and planar Goubau lines (PGLs) [3], although coplanar waveguide has also been used at lower (GHz range) frequencies [4]. In previous PGL work [3], microfluidic channels were overlaid perpendicular to a single-wire transmission line, and a vector network analyser (VNA) used to excite the probing electric field.…”