Miniaturized microstrip Marchand balun and coupled-line section as microwave sensor for dielectric material detection

A novel method of dielectric sample detection has been presented. The proposed measurement setup is composed of coupled-line section sensor inserted in-between two identical Marchand baluns, which provide differential excitation to the sensor. The setup allows for measurement of dielectric samples of size as small as separation between sensor's coupled strips. The proposed sensor has been theoretically investigated and confirmed by EM simulations. Additionally, the utilized miniaturized Marchand balun has been manufactured and measured. The obtained results prove the usefulness of the presented approach.