Design and implementation of an S-band near-field focused array with high E-field strength

An S-band near-field focused array is designed and implemented. Consisting of 4 × 4 metallic Vivaldi elements, the array is designed for focusing the E-field of several kilovolts per metre within its near-field region. To minimise the power loss and enhance the synthesis effectiveness, elements are arranged on a sphere surface and oriented towards the sphere centre. When exciting the elements, the waves will be focused to a specific area on the observation plane. By adjusting the excitation phase, the focus position can be tuned. A systematic analysis has been carried out to illustrate the focus scanning process across the entire observation plane. Near-field two-dimensional scanning is performed to measure the E-field distribution of the array. While scanning the focus, the diameter of 3 dB focal area is about 0.3 m, and the maximum field strength in the focus ranges from 1184 to 2129 V/m, which can be used for the radiated susceptibility testing.