High-Frequency Field-Sensing Coils Using Microstrip Lines

Abstract

We developed a high-frequency field-sensing coil that uses a microstrip line. The usable frequency range of the coil is higher than that of conventional two-terminal coils, but yields only a low voltage per unit of coil area. The output voltage of the coil depends largely on the design of the ground plane of the microstrip; The ground plane pro vides impedance matching of 50 ohms but also weakens the magnetic field across the microstrip coil pattern because of eddy current generation. The optimum design of the coil depends on this trade-off.