Dual-band radio-frequency device for sensing dielectric property changes in microfluidic channel

We propose a dual-band RF device to detect the dielectric changes in polydimethylsiloxane (PDMS) microfluidic channel. Such a device, which consists of two dual-band Wilkinson power dividers (working at 2GHz and 5GHz) and two 90° dual-band microstrip lines (providing 180° phase difference at two working frequencies), is very sensitive for identifying dielectric material changes. Moreover, by operating at two frequencies simultaneously, it can improve the measurement stability/robustness. Compared with the recently reported RF microfluidic sensor [Yang et al, Lab Chip, 10, 553, (2010)], the proposed device features enhanced measurement stability with the same level of measurement sensitivity (-80dB cancellation level).