Ultrawideband monopole antenna for use in a circular cylindrical microwave imaging system

Abstract

Abstract A novel ultrawideband printed monopole antenna for use in a circular cylindrical microwave imaging system is presented.The proposed antenna consists of a square radiating patch and a modified ground plane with an open circuit structure slit and an inverted π‐shaped parasitic structure, which provides a wide usable fractional bandwidth of more than 130% (2.91–14.72 GHz). By cutting an open circuit structure in the ground plane and also by inserting an inverted π‐shaped parasitic structure in the ground plane, additional resonances at 11.5 and 14.2 GHz are excited and hence much wider impedance bandwidth can be produced, especially at the higher band. Unlike other antennas reported in the literature to date, the proposed antenna displays a good omnidirectional radiation pattern even at higher frequencies, and also its radiation efficiency is greater than 87% across the entire radiating band. The designed antenna has a small size of 12 × 18 mm 2 . Simulated and measured results are presented to validate the usefulness of the proposed antenna structure for circular cylindrical microwave imaging systems. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2202–2205, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27041