Design of Wideband Conformal Vivaldi Antenna Array

This paper presents a Vivaldi antenna designed for IEEE C-band applications from 4.3 to 9.8 GHz with the aim of achieving -10 dB bandwidth from 4–9 GHz with a gain of 5–9 dBi throughout the band. The designed Vivaldi antenna is fed through a microstrip line for smoother slot transition. The Vivaldi antenna was used to develop a conformal antenna array for wide-angle beam scanning mounted on the periphery of a sphere which provides 360° beam scanning in the azimuthal plane and
$\pm 30^{o}$
in the elevation angle. Vivaldi antenna provides a maximum realized gain of 8.32 dBi gain at 7 GHz at
$\theta=0^{o}$
. Two different antenna arrays are presented. The first antenna array consists of
$1\times 5$
antenna elements and provides a beam scanning capability of
$\theta=\pm 30^{0}$
in the
$\phi=90^{o}$
plane with a realized gain of 13.79 dBi, 12.56 dBi, and 12.00 dBi at the target scan angles of
$\theta_{t}=0^{o},\ 15^{o}$
, and
$\theta_{t}=30^{o}$
respectively. Finally, a 3-D conformal Vivaldi antenna array is presented with a maximum realized gain of 19.97 dBi gain at
$\theta=0^{o}$
. ANSYS HFSS was used to verify the validity of the designs.