A Broadband Millimeter-Wave Vertically-Integrated Vivaldi Antenna and Its Circularly Polarized Array

A novel broadband millimeter-wave(mm-Wave) vertically-integrated Vivaldi antenna with stable gain and good radiation patterns is presented in this paper. The proposed antenna element consists of five substrates. There are two symmetrical metal radiation strips on the top of each substrate. The two adjacent stripes are connected through the metallized via. A coupling-slot on the substrate integrated waveguide(SIW) is employed as the feeding structure to these strips. Simulations show that the antenna can have a wider impedance bandwidth of 28%, and a higher gain of 8 dBi. In addition, based on this antenna element, a 2×2 circularly polarized(CP) antenna array is designed to demonstrate that the proposed antenna is a promising candidate for the mm-Wave CP applications. The 2×2 array exhibits an impedance bandwidth of 16.8% and axial ratio(AR) bandwidth of 16.6% with the good right-hand CP radiation patterns.