Extremely Low-Profile BOR-SPR-SLOT Antenna With Stop Bands

An antenna, composed of a body of revolution (BOR), a shorted parasitic ring (SPR) printed on a dielectric substrate, and a ground plane, is investigated for generating a stop band within the frequency response band of the VSWR. For this, slots are cut into the SPR, where the height of the SPR is approximately 0.067 wavelength at the lower bound frequency. The antenna is designated as the BOR-SPR-SLOT. The effects of the slot length, slot location angle, and slot width on the stop band are analyzed. Furthermore, the antenna characteristics, including the radiation pattern and gain are revealed and discussed. It is found that the stop band within an extremely wide frequency band (150%) appears when the slot length corresponds to approximately one-quarter guided wavelength. It is also found that the radiation pattern at frequencies outside the stop band remains almost unchanged. Based on these findings, two stop bands are also generated using slots of different lengths.