Sensitive Spectroscopy Using DSRR Array and Linvill Negative Impedance

Wideband spectroscopy is used in microwave regime for selective material characterization, where narrowband resonant methods offer better sensitivity. This paper presents a unique integration of these two techniques with ultrahigh resolution using an oscillator array. Four double split ring resonators, designed to resonate at f
_τ1
= 3.097 GHz, f
_τ2
= 3.420 GHz, f
_τ3
= 3.784 GHz, and f
_τ4
= 4.352 GHz. This is accompanied with a negative impedance converter circuitry that helps the resonators oscillate simultaneously. The oscillator array presents highly precise wideband spectroscopy of liquids with maximum error of 2% and limit of detection of 0.5% methanol in water concentration.