A Miniaturized and Ultra-Wideband Antipodal Vivaldi Antenna With Triangular Slots

A miniaturized and ultra-wideband antipodal Vivaldi antenna with triangular slots is proposed in this paper. The antenna adopts the antipodal Vivaldi structure and gradient trapezoidal microstrip line feed to realize miniaturization. Through opening triangular slots on the patch, the antenna can be further miniaturized. The lowest frequency of the simulated antenna can reach 4.2 GHz and the size is
$30\mathbf{mm}\times 30\mathbf{mm}\times$
1mm. Impedance bandwidth of the proposed antenna is starting from 4.2GHz to more than 20 GHz, and the highest and lowest frequency ratio of the antenna is more than 5. Loading symmetrical square parasitic patches on both upper and lower layers, the simulation results show the gain is improved in the range of 11GHz to 19GHz, and the maximum increase is 1.7dBi.