A Nondestructive Method for Measuring the Complex Permittivity of Thick Slab Specimen Using the Improved Open Waveguide Method Based on the NRW Method. - Kitae Park; Jung-Hwan Lim; Han-Hee Lee; Chang-Hee Hyoung; Jung-Hwan Hwang; Jong-Hwa Kwon; Jae Wook Lee (IEEE Trans. Instrum. Meas., 2025)