Cavity Backed Patch-Slot Antenna for Lower Band 5G Communications

A cavity-backed patch antenna covering two 5G frequency bands under 6 GHz range is proposed. Good performance is obtained by optimizing the geometry of a rectangular slot and the embedded rectangular patch as well as the supporting cavity. The impedance matching between the antenna and the co-planar waveguide excitation feeding line is optimized to cover two 5G bands from 3.38 GHz to 4.35 GHz. The antenna gain is 5.68 dBi at the center frequency 3.95 GHz. A 1x5 linear array of this antenna element yields 12.03 dBi gain at the broadside with uniform excitation and up to 30 degrees beam scanning angle with phased excitation. With the additional metal ground plane, the gain of a 1x15 linear array reaches 19.28 dBi. The geometrical properties of this simple antenna structure and its good radiating performance make it a great potential for 5G base station antenna arrays.