Triple-Band Microstrip Patch Antenna and its Four-Antenna Module Based on Half-Mode Patch for 5G 4 × 4 MIMO Operation

To meet the demands of the new frequency bands and the 4times 4 multiple-input multiple-output (MIMO) specification brought by fifth generation (5G), a triple-band microstrip patch antenna and its four-antenna module are proposed. Based on the half-mode microstrip patch, the first three modes of TM1/2,0, TM1/2,1, and TM3/2,0 that can be independently tuned are engineered to cover the three Chinese 5G bands (N41/N78/N79). The proposed triple-band microstrip patch antenna with the volume of 33.5times 32.5times 4 mm3 shows the -6 dB frequency bands of 2.47-2.75 GHz, 3.39-3.60 GHz, and 4.69-5.10 GHz, which makes a nice compromise between antenna volume and impedance bandwidths. Four such patches are arranged in a sequentially rotated style to constitute the triple-band four-antenna module, which is with the volume of 71times 71times 4 mm3. Measured results of the module show high performance. The reflection coefficients of the four elements are almost identical: the bandwidths are 2.50-2.75 GHz, 3.41-3.62 GHz, and 4.68-5.01 GHz; all the isolations are better than -13.3 dB; the average total efficiencies of the four elements are between -1.41 and -1.11 dB, -2.45 and -2.10 dB, and -1.81 and -1.53 dB for N41, N78, and N79, respectively; and all the envelope correlation coefficients (ECCs) are lower than 0.07.