A High Gain, UWB Vivaldi Antenna Loaded With Unit Cells for Imaging /RFID Applications

A miniature Vivaldi antenna with high gain and ultrawideband (UWB) characteristics is presented in this paper by etching grooves coupled with meandered unit cells. Further, slots at the aperture and the Artificial Material Lens (AML) at the CVA's flank are used to boost the gain over the wider frequency band. The designed antenna has almost endfire radiation patterns, a peak realized gain of 10 dBi and an average gain of more than 4.8 dBi over the complete range. This gives a gain improvement of up to 2.5 dB over the conventional Vivaldi antenna in the operating range of 4.7 to 12.3 GHz with return loss $(\vert \mathrm{S}11\vert)$ below -10 dB. The antenna has been designed over a low-price FR4 substrate with a thickness of 0.8 mm (65 mm x 40 mm) which makes it an interesting candidate for different imaging / RFID applications.