In recent years, we have witnessed unprecedented advances in electronic technology across multiple application domains, particularly within the biomedical field. Among the countless possibilities, technologies based on the propagation of electromagnetic fields, such as microwaves or millimeter waves, are emerging as potential instruments for the non-invasive measurement of specific biomarkers. In this tutorial, we will acquaint ourselves with the fundamental operating principles of these measurement technologies, illustrating them specifically through the measurement of blood glucose concentration, an essential biomarker for diabetes. This tutorial will review the fundamentals of remote measurement via electromagnetic means and the main detection approaches. Then, a practical example will be shown with valuable design and implementation hints, with special emphasis on the right selection of measurement metrics. Finally, some recent works exploiting this measurement approach will be discussed, underscoring the current challenges and enticing future prospects of this technology.
