This disclosure provides a dielectric sensor configured to detect a physiological variable within a subject. The dielectric sensor having at least one split-ring resonator configured to be positioned within an oral cavity of the subject and to be bioresponsive to at least one physiological variable. The split-ring resonator having a first resonator loop, a second resonator loop, and a dielectric interlayer interposed between and contacting the first resonator and the second resonator.
