นามแสง อ. A Bandpass Filter Using Symmetrical Coplanar Structure without backed ground plane. Front. Eng. Innov. Res. [internet]. 2002 Dec. 30 [cited 2025 Jan. 17];2:64-8. available from: https://ph01.tci-thaijo.org/index.php/jermutt/article/view/242373