Background The Institute of Applied Electronics, China Academy of Engineering Physics, has developed a three-dimensional (3D) omnidirectional sensor capable of measuring pulsed fields with nanosecond pulse widths, field strengths up to hundreds of kV/m, and a large dynamic range. This sensor exhibits excellent 3D omnidirectional measurement capability. However, whether this sensor can accurately measure cavity coupled fields has not yet been investigated.

Purpose This study aims to evaluate the sensor's capability for measuring cavity coupled fields and achieve accurate measurement of such fields using the sensor.

Methods A simulation study on the measurement of coupled fields inside cubic metallic cavities with the 3D omnidirectional sensor was conducted using FDTD electromagnetic simulation software. Measurement results of the sensor under different conditions (cavity size and measurement position) were obtained. By calculating the peak deviation and waveform cosine similarity of the measurement results, the feasibility of applying the sensor to the accurate measurement of high-power electromagnetic pulse cavity coupled fields was analyzed from the perspectives of amplitude measurement and waveform measurement.

Results Simulation results show that the peak deviation of the sensor measurement decreases as the cavity size increases. When the cavity size increases from six times the sensor size to twenty times the sensor size, the peak deviation decreases from 2.5 dB to 0.7 dB. Meanwhile, the waveform cosine similarity increases with cavity size, rising from less than 20% to 98%. The measurement position has a relatively minor effect on the sensor measurements; the peak deviation at various positions exhibits only slight fluctuations, with a variation within ±0.3 dB, and the waveform cosine similarity also shows only minor variations, with a fluctuation range of less than 3%. However, when the cavity size increases to fourteen times the sensor size or larger, a slight decrease in similarity is observed at the location approximately one-quarter of the cavity side length from the wall.

Conclusions This sensor is capable of accurately measuring cavity coupled fields. Its measurement accuracy improves with increasing cavity size and exhibits a high degree of consistency within the same cavity. On this basis, engineering testing recommendations for the 3D omnidirectional sensor in cavity coupled fields are further proposed, providing a reference and guidance for high-precision measurement of cavity coupled fields.