SummaryThis 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 εr = 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.