A low-profile vertical polarized omnidirectional radiated and broadband printed antenna

In this paper, a low-profile vertical polarized omnidirectional radiated and broadband printed antenna was proposed. This antenna forms a transmission lines structure similar with parallel lines by using metal vias and coaxial feed inner conductor. Then the distributed inductances and capacitances of transmission lines are used to yield resonance with loaded capacitance of antenna itself. Therefore, this structure can realize wide range of working frequency and has omnidirectional radiation characteristics. The simulated results by CST Microwave Studio software indicate that the reflection coefficient of the antenna is less than −10dB and relative bandwidth is up to 49% from 2.40GHz to 3.95GHz. Also, the corresponding omnidirectional gain is up to the range from 1.3 dBi to 4.2 dBi. The dimension of this vertical polarized antenna is 10mm on the polarization direction, which is only 8% of the lowest working frequency corresponding to the wavelength. Hence, the antenna achieves well low-profile effects. The working frequency band covers WLAN/WiMAX bandwidths.