Multiband High-Gain Vivaldi Antenna with Loaded Elements for Millimeter-Wave Applications

A miniaturized high-gain Vivaldi antenna printed on a thin substrate is proposed for operation as multi-band antenna for millimeter-wave applications. The design is compact size and the dimensions of its arms are optimized. To maximize the gain within a selected frequency band, each arm of the Vivaldi antenna is loaded by a ring-shaped parasitic element. The dimensions and location of the parasitic ring are optimized to produce the maximum gain. The results of the parametric study for the optimization of the design parameters regarding the parasitic ring are presented and discussed. The antenna is fabricated and subjected to performance evaluation through measurements. It is shown that the antenna impedance is matched to 50 Ω over the four frequency bands centered at 24.85, 34.75, 44.05, and 54.20 GHz. The corresponding bandwidths are 5.7, 5.5, 5.1, and 5.0 GHz, respectively with percent bandwidths of 23%, 16%, 11. 6%, and 9. 2%, respectively. The proposed Vivaldi antenna is fabricated and subjected to measurement for experimental investigation of its performance. The measurement show good agreement with the simulation results.