In this paper a compact antipodal Vivaldi antenna with dimensions of 40×85 mm2 for Ka band is presented. To enhance the antenna gain, epsilon near zero metamaterial (ENZ) unit cells are embedded at the same plane of the Vivaldi flare aperture. These ENZ unit cells have the advantage of confining the radiated fields with additional compact size. The obtained antenna exhibits an ultra-wide bandwidth from 23 GHz to 40 GHz with a reflection coefficient less than -10 dB. This is suitable for 5G applications at both 28 and 38 GHz. The antenna gain in this frequency band is found in the range from 14 to 17.2 dBi. The proposed antenna is designed by using CST-MW Studio, and the results are verified with experimental measurements.
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