Abstract: A device for measuring the glucose level in living tissue has electrodes (5, 6) for being brought into contact with the specimen and a voltage-controlled oscillator (31) as a signal source for generating an AC voltage in a given frequency range. The AC voltage is applied to the electrodes (5, 6). A voltage over the electrodes is fed to a processing circuitry (37, 38), which converts it to the glucose level using calibration data. The voltage-controlled oscillator (31) has a symmetric design with adjustable gain for generating signals in a large frequency range with low distortions at a low supply voltage. The processing circuit comprises a simple rectifier network with software-based correction. The electrodes (5, 6) are of asymmetric design and optimized for biological compatibility.

Abstract: A device for measuring a glucose level or some other parameter of living tissue that affects the dielectric properties of the tissue is disclosed. The device comprises an electrode arrangement (5) having a plurality of electrodes (5-i). The signal from a signal source (31) can be applied to the electrode arrangement via a switching assembly (39). The switching assembly (39) is designed to selectively connect a first and a second pattern of the electrodes (5-i) to the signal source, thereby generating a first and a second electrical field with different spatial distribution in the tissue. By using a differential method which relies on measuring the impedance of the electrode arrangement (5) for each field and on suitable subtraction of the measured results, surface effects can be reduced and the focus of the measurement can be offset to a point deeper inside the tissue.