Mohd Tarmizi Ali and  Mohd Khairul Mohd Salleh and  Md. Mahfudz Md. Zan,  Air-Filled Circular Cross Sectional Cavity for Microwave Non-Destructive Testing.   journal   = {International Journal of Mechanical and Mechatronics Engineering}, [online]. World Academy of Science, Engineering and Technology.
    June 2008, vol. 18(6). 809 - 814
    [viewed 07 December 2021]. Available from: https://publications.waset.org/pdf/4485.