A novel vivaldi antenna with extended ground plane stubs for ultrawideband applications

In this letter, a compact printed Vivaldi antenna with two symmetrical extended ground plane stubs is presented. By extending the stubs from the ground plane, the low-end bandwidth limitation of the antenna is extended to low frequencies and then the bandwidth is enlarged. To validate the proposed design, an antenna prototype is fabricated and tested. The measured results confirm that the modification presented in this letter is very effective without changing the overall dimensions of the antenna. The measured impedance bandwidth defined by S11 < −10 dB is from 2.45 to 15.2 GHz with a ratio of about 6.2:1. The measured gain is better than 4.2 dBi within the operating frequency band. In addition, a nearly constant group time delay is also achieved across the band of 2.4–16 GHz. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:983–987, 2015