Design of Dual-Band/Wideband Dipole MIMO Antennas Using Center-Loaded Stubs

In this paper, a design method for dual-band and wideband MIMO antennas is presented. Two stubs are loaded at the center point of a dipole antenna so that two hybrid modes can be generated. For the dual-band design, the fundamental mode works at a lower frequency while the second harmonic mode works at a higher frequency. For the wideband design, the original main stub of the dipole antenna works at a lower frequency, and half of the main dipole together with the loaded stubs works at a higher frequency. The dual-band antenna's optimal frequency range is 3.4 - 3.6 GHz and 4.7 - 5 GHz, and its isolation is greater than 18 dB with an ECC of less than 0.025. The final optimized wideband MIMO antenna achieves isolation of better than 15dB across the desired N78 band, from 3.3 to 3.8 GHz, with an ECC of less than 0.17.