A Compact Coplanar Vivaldi Antenna with L-shaped Slotline

A compact coplanar Vivaldi antenna with L-shaped slotline is presented. The L-shaped slotline consists of the exponential tapered slot and a linear slotline. The linear slotline is utilized to replace the circular cavity in traditional coplanar Vivaldi antenna and acts as open circuit to provide a good impedance match for low frequencies. The simulated results indicate that the demonstrated compact geometry can achieve the miniaturization of the antenna which is commonly realized by loading high resistance in the past, and the E-plane width of the antenna is just about
$0.26\lambda_{0}$
at the minimum frequency, without any loading.