A design of 120-degree vertical polarized sector antenna using very short balanced antipodal Vivaldi antenna

The Vivaldi antenna is a very popular antenna element for those applications requiring a high-gain and a wideband traveling wave antenna element. The antenna usually has very long length L (≥3λ₀). Following basic traveling-wave antenna principles, the longer L, the higher the gain and narrower the beamwidth. Very few references appear in the literature where this antenna element is used in its very short form, i.e. (L≤λ₀/2). A short form Vivaldi antenna is used for the sector antenna application. With the help of reflectors, the design can give a 120° horizontal beamwidth.