A High Gain UWB Vivaldi Antenna Loaded with Elliptical Slots

A high gain and ultra-wide band(UWB) planar printed Vivaldi antenna loaded with elliptical slots is presented in this paper. The antenna consists of a layer of substrate and two exponentially tapered slot patches, which forms an antipodal structure. A set of symmetrical elliptical slots are loaded on the two arms of the patches, respectively. The antenna gain is increased by about 1 to 2.6dB within the frequency range of 7 to 25GHz, while the matching performance at the low frequency band is also improved. Metal vias and semi-circular slots are loaded on both sides of the microstrip feedline to improve the transmission performance at the high frequency band. According to the simulated results, the relative bandwidth of the reflection coefficient less than -10dB is 145% (6.4GHz-40GHz) with the center frequency of 23.0GHz. The simulated gain of the antenna is about 8dBi in the 6.4–17.5GHz band, and greater than 10dBi in the 17.5–40GHz band with the maximum gain of 11.3dBi. Within above band, the cross polarization is less than -15dB.