An Ultra-Wideband BOR-SPR Antenna Backed by a Conical Ground Plane

We propose a BOR-SPR antenna that achieves improvement in the minimum gain in the horizontal direction. For this, the ground plane is bent in a conical shape. The minimum gain is improved by 5 dB compared to the case of using a planar ground plane. The proposed antenna exhibits an almost isotropic pattern in the horizontal plane. The input impedance bandwidth <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\left(\left\vert S_{11}\right\vert \leq-6 ~\text{dB}\right)$</tex> is 160%.