Study on low profile wideband antenna

A low profile Ultra-wideband omnidirectional antenna is proposed in this paper. The new designed antenna is with good performance over 225MHz to 400MHz. The structure of the proposed antenna consists of a column with four annular semi-elliptic elements (C-FASE), top loaded by a circular “hat” which is shorted to the square ground plane with four symmetrical stub. The notch filtering is realized by inserting a metallic column to two orthogonal annular elliptic slices with different resonant frequencies which couple together to form a wider frequency bandwidth. The height of the new antenna is 0.05λ₀, where λ₀ is the wavelength of the low frequency.