Very Low-Profile Top-Loaded UWB Coupled Sectorial Loops Antenna

In this letter, we present a new very low-profile monopole-type antenna. The proposed antenna height is 0.053λ₀, where λ₀ is the minimum operating wavelength and operates over 148% relative bandwidth. The antenna is based on the principle of top-loading of coupled sectorial loop antenna (CSLA). Introducing a series capacitive gap in the top-loading plate and the CSLA fins allows for achieving ultrawideband operation and very low antenna height simultaneously. The proposed structure is also relatively easy and cost-effective to fabricate using standard printed circuit board (PCB) fabrication technology. A parametric study is presented to show the effect of the different dimensions on the antenna performance. A prototype antenna is fabricated and measured. The measurements and simulation results show good agreement and indicate that a VSWR <; 2 over 0.9-6 GHz can be accomplished. It is also shown that the radiation pattern has omnidirectional characteristics over more than two octaves.