Metamaterial-inspired miniaturized and broadband U-slotted patch antenna for the 5G communications covering the full N78 band

This work presents a new miniaturized and broadband metamaterial-inspired U-slotted patch antenna (MUPA), aiming to cover the full N78 band in the 5G mobile communications. Two techniques as the mushroom metamaterials and U-slotted patch are synthetically used in the MUPA. A particular MUPA is designed with low-cost low-index substrates with ε_r = 2.2 and further demonstrated in experiments. It is found that the new antenna has an operating bandwidth of 3.30 to 3.82 GHz (14.6%). The patch length is only 18 mm (0.21λ, λ is the wavelength at the center frequency 3.56 GHz). The radiation characteristics of the MUPA are also studied in experiments. The measured antenna gain is 5.54 dBi whereas the cross-polarizations are successfully suppressed lower than −16 dB, making the MUPA promising to meet the demands of 5G mobile communications.