Compact UWB Resistor Loaded Planar Antenna with Omni-directional Radiation

This paper presents a compact, coaxially-fed planar antenna that exhibits omnidirectional characteristics within an ultra-wideband operational bandwidth of 0.5 GHz to 9.5 GHz. The proposed antenna is derived from the ellipse printed dipole antenna, with a reduction in the volume of the radiation patch at one end based on the ellipse printed dipole antenna. Simultaneously, a curved structure is incorporated at the edge of the radiation patch at the other end, along with a groove excavation and resistor loading. This configuration ensures that the antenna maintains a voltage standing wave ratio (VSWR) less than 3 and a gain greater than -5 dBi across its operating frequency range. Compared to traditional antennas, it offers improved compactness, superior omnidirectional radiation patterns in the H-plane, and a planar structure.