A microwave field-detecting needle assembly includes a needle assembly. The needle assembly includes a distal portion, a proximal portion, and a junction member disposed between the distal portion and the proximal portion. The junction member includes a recess defined therein. The needle assembly also includes a rectifier element disposed in the recess. The rectifier element includes a first terminal electrically coupled to the distal portion and a second terminal electrically coupled to the proximal portion.
