An Accurate and Compact Reflection Measurement Module towards Microwave Dielectric Measurement of Biological Samples

A 4–9 GHz reflection measurement module for dielectric measurement of biological samples is proposed. The module has a compact size of 120 × 55 × 13 mm. To compensate for the number of components and power consumption, we propose an architecture composed of one transmitter, receiver and an SPnT switch and the stability of the phase signal was 0.004 degrees in a 2-h continuous measurement. Furthermore, we demonstrate in vitro measurement of an aqueous solution of glucose using the module. The dielectric constant shows good agreement within 1.5 % error compared with that measured by a vector network analyzer. This module is expected to be used for novel biological applications such as noninvasive sensing and SAR evaluation.