Bandwidth Extension of PCB Rogowski Coils Using Distributed Damping

PCB Rogowski coils are commonly used sensors for wide-band current measurements due to their low cost, high bandwidth potential and ease of integration into existing systems. However, their performance is currently constrained by a trade-off between their maximum frequency of operation and their low-frequency sensitivity. In this paper, a novel distributed damping network capable of significantly extending the bandwidth of PCB Rogowski coils with minimal impact on their low-frequency mutual inductance is proposed. A complete modeling framework and two numerical methods that implement it with different levels of fidelity are presented. These methods accurately predict the high-frequency response of a sensor equipped with the proposed network under realistic measurement conditions, and achieve nearly an order-of-magnitude speedup compared to existing full-wave solvers. Using a custom test fixture, alongside the fabrication of a wide array of sensors implementing the proposed networks, the theoretical predictions of the models are validated experimentally. A fivefold increase in the −3 dB bandwidth of the fabricated PCB Rogowski coils is demonstrated, with negligible impact on their low-frequency sensitivity and at the cost of only two additional resistors per turn.