Analysis of a Broadband Low-Profile Two-Strip Monopole Antenna

A broadband low-profile monopole antenna is analyzed by using balanced and unbalanced mode decomposition. The broadband antenna consists of an S-strip and a folded T-strip that are separately printed on the two sides of a thin planar substrate, forming a two-strip monopole. The two-strip antenna can achieve a bandwidth (VSWRles2) of ~40% with a height of 0.08lambda
₀
. It is revealed that the broadband performance of the two-strip antenna is a result of the combination of an unbalanced mode and a balanced mode. Experimental results verify the theoretical analysis.