“…The frequency response of the defect mode that depends on the OPEN 1 TH-PPM Group, Physics Department, Faculty of Science, Beni-Suef University, Beni-Suef 62521, Egypt. 2 Department of Mechanical Engineering, College of Engineering, King Khalid University, 61421 Abha, Saudi Arabia. * email: zaky.a.zaky@science.bsu.edu.eg change in the gas sample's acoustic properties, which fills the structure, will be studied.…”