title: A simple, tunable, and highly sensitive radio-frequency sensor.
abstract: We report a radio frequency (RF) sensor that exploits tunable attenuators and phase shifters to achieve high-sensitivity and broad band frequency tunability. Three frequency bands are combined to enable sensor operations from ∼20 MHz to ∼38 GHz. The effective quality factor (Qeff) of the sensor is as high as ∼3.8 × 106with 200μl of water samples. We also demonstrate the measurement of 2-proponal-water-solution permittivity at 0.01 mole concentration level from ∼1 GHz to ∼10 GHz. Methanol-water solution and de-ionized water are used to calibrate the RF sensor for the quantitative measurements.
authors.affiliation: Department of Electrical and Computer Engineering, Clemson University, South Carolina 29634, USA.
authors.forename: Yan
authors.initials: Y
authors.lastname: Cui
authors.forename: Jiwei
authors.initials: J
authors.lastname: Sun
authors.forename: Yuxi
authors.initials: Y
authors.lastname: He
authors.forename: Zheng
authors.initials: Z
authors.lastname: Wang
authors.forename: Pingshan
authors.initials: P
authors.lastname: Wang
references.citation: Nature. 2003 Feb 27;421(6926):925-8
references.pmid: 12606995
references.citation: Lab Chip. 2010 Mar 7;10(5):553-5
references.pmid: 20162228