A Decoupling and Matching Network With Harmonic Suppression for MIMO Antennas

This article presents a decoupling and impedance matching network with harmonic suppression for two-element antenna arrays, including a resistor-loaded decoupling part and a slotline-based impedance matching and harmonic suppression part. By integrating with the proposed network, the mutual coupling between the elements at the center frequency can be well suppressed. Moreover, the second-order harmonic is also suppressed to a low level. For verification purposes, a 2×2 dual-polarized antenna array centered at 3.5 GHz is employed and integrated with the proposed networks. A 3-D model is constructed and full-wave simulations are carried out. The results denote that the strongest in-band mutual coupling is suppressed from -16.6 dB to less than -25 dB, and a good out-of-band rejection level up to 10 GHz is obtained.