Loop Antenna Driven Double Microwave Resonator-Based Sensors Incorporating PDMS Microchannels on Glass Substrates

Abstract

Microwave resonator-based sensors offer low-cost, contactless, label-free sensing solutions in a variety of applications. Sensing is done by the observation of the shifts in resonant frequency of the sensor structure, which depends on resonator geometry, material and physical properties of the environment. It is observed that the readings can be significantly affected by changes in secondary physical parameters or sample localization on resonator. A double microwave resonator sensing system incorporating microchannels on glass substrates are proposed to address these challenges. PDMS microchannels bonded on glass substrates are mounted on split ring resonators fabricated via low-cost processes. Experiments are performed with glucose solutions of 1.4 mg/mL–3.0 mg/mL concentration range. Results confirm that the use of double resonators increase rejection of background noise, whereas microchannel use increases measurement stability. Overall measurement sensitivity is shown to be 0.92 MHz/(mg/mL). Further improvements are aimed with the bonding of microchannels directly on resonators fabricated on glass substrates.

A fully integrated biosensing platform combining acoustofluidics and electromagnetic metamaterials

“…Therefore, Cb decreases with concentration of glucose, whereas Lm generally stays constant. Thus, the resonant frequency increases with the glucose concentration as demonstrated before21 .…”

Gold-on-glass microwave split-ring resonators with PDMS microchannels for differential measurement in microfluidic sensing

“…These systems were tested within various ranges of glucose concentrations and some track the change of the magnitude of the reflection/ spectra response, instead of the change of f 0 . Of the sensor systems It is seen that the sensitivity of the sensor to in aqueous solutions, which is expressed in this work as the shift in f 0 per change in concentration, was kept high in the order of similar sensors shown in the literature, 41,42 which is related to high Q of the measuring SRR. This was possible due to the selected geometry for the SRR and the maintenance of a high Q.…”

“…Microchannels were integrated to resonator sensors to address this issue, enabling the use of resonator sensors in microfluidics. 25,[41][42][43] One further step in the development of electromagnetic resonator-based sensors was taken with the use of a pair of sensor structures instead of a single one. 44,45 One of the resonators in this approach is providing a reference reading from the background, so that the ambient variations can be canceled out with differential measurement of outputs from both sensors.…”