EFFECTIVE RELATIVE PERMITTIVITY OF 3D-PRINTED HIGH-IMPACT POLYSTYRENE STRUCTURES IN THE MICROWAVE FREQUENCY RANGE. techeng [Internet]. 2026 Oct. 5 [cited 2026 Nov. 2];27(4):20-33. Available from: https://jrnl.knutd.edu.ua/index.php/techeng/article/view/2111