A high‐order emsiw mimo antenna for space‐constrained 5g smartphone

Abstract

This paper proposes a high‐order MIMO antenna operating at 3.5 GHz for a 5G new radio. Using an eighth‐mode substrate integrated waveguide (EMSIW) cavity and considering a typical smartphone scenario, a two‐element MIMO antenna is developed and extended to a twelve‐element MIMO. These MIMO elements are closely spaced, and by employing multiple diversity techniques, high isolation is achieved without using a decoupling network. The asymmetric EMSIW structures re-sulted in radiation pattern diversity, and their orthogonal placement provides polarization diversity. The radiation characteristics and diversity performance are parametrically optimized for a two‐element MIMO antenna. The experimental results exhibited 6.0 dB and 10.0 dB bandwidths of 250 and 100 MHz, respectively. The measured and simulated radiation patterns are closely matched with a peak gain of 3.4 dBi and isolation ≥36 dB. Encouraged with these results, higher‐order MIMO, namely, four‐ and twelve‐element MIMO are investigated, and isolation ≥35 and ≥22 dB are achieved, respectively. The channel capacity is found equal to 56.37 bps/Hz for twelve‐element MIMO, which is nearly 6.25 times higher than the two‐element counterpart. The hand and head proximity analysis reveal that the proposed antenna performances are within the acceptable limit. A detailed comparison with the previous works demonstrates that the proposed antenna offers a simple, low‐cost, and compact MIMO antenna design solution with a high diversity performance.