A novel radiating structure for close range radiated immunity measurements

A conformal test cell has been constructed and its performance measured as an EM immunity monitor. A compact ferrite lined cell of 1 m ³ volume has been designed using a broadband planar antenna as the source instead of a septum as is used in most test cells of this size. The degredation in isolation due to the close proximity of the EUT and antenna is compensated for by embedding the antenna in a lossy dielectric material. The complex material permittivity has the effect of increasing the electrical length separating the two and the imaginary component introduces some loss into the system further improving the antenna isolation. Studies are presented of the interaction between the material and the antenna and the resulting performance of the antenna in a cell as an immunity measuring device. The field uniformity, power requirement to generate 10 V/m modulated field and the current distribution on a metallic EUT are considered