Microwave Non-destructive Technique using a Double-ring Resonator for Classification of Transparent Flesh and Yellow gum MangosteensCahyo Mustiko Okta Muvianto, Kurniawan Yuniarto, Suthami Ariessaputra, Sudi Maryanto Al Sasongko, Budi Darmawan and Syafaruddin ChE3S Web of Conf., 465 (2023) 02063DOI: https://doi.org/10.1051/e3sconf/202346502063