Fast Readout of Split-Ring Resonators Made Simple and Low-Cost for Application in HPLC

authored by
Moritz Hitzemann, Kirsten J. Dehning, Adrian V. Gehl, Erk Fietje Sterr, Stefan Zimmermann
Abstract

Split-ring resonators (SRR) are simple electrical circuits that show a significant shift in resonance frequency even with the smallest changes in split capacitance, and thus in permittivity, electric conductivity, and dielectric losses of the split capacitor’s dielectric. Usually, the resonance frequency is derived from the frequency response, but recording the frequency spectrum takes a certain amount of time. Here, we present a new capillary split-ring resonator CaSRR with fast readout for liquid chromatography (LC), which is capable of accurately detecting very fast changes in split capacity. The proposed method is based on the detection of the transmitted signal at a single frequency that is analyzed by demodulation. The demodulated signal changes its amplitude depending on the shift of the resonance frequency. Our simple low-cost electronics enables an average sampling rate of 42 Hz with 128 averages of the demodulated signal and has a frequency stability of 840 mHz. Thus, a minimum change in permittivity of ∆εr,min = 11.26 × 10−3 can be detected. Finally, a chromatogram of one sugar (glucose) and one sugar alcohol (xylitol) is recorded using the SRR and is compared to a standard refractive index detector.

Organisation(s)
Sensors and Measurement Technology Section
Mixed-Signal Circuits Section
Type
Article
Journal
Electronics (Switzerland)
Volume
11
No. of pages
14
ISSN
2079-9292
Publication date
04.04.2022
Publication status
Published
Peer reviewed
Yes
ASJC Scopus subject areas
Control and Systems Engineering, Signal Processing, Hardware and Architecture, Computer Networks and Communications, Electrical and Electronic Engineering
Electronic version(s)
https://doi.org/10.3390/electronics11071139 (Access: Open)