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 resulted 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.
Highlights
The 5G new radio (NR) technology has paved the way for enhanced mobile broadband services, which allow the exchange of high data rates [1], and provides an opportunity for developing antennas for such applications, operating in the sub-6 GHz band (i.e., FR1) and millimeter-wave band (i.e., FR2)
A shift in operating frequency from 3.56 GHz in full-mode SIW (FMSIW) to 3.025 GHz in the eighth-mode substrate integrated waveguide (EMSIW) was primarily due to the fringing effect around two quasi-magnetic walls, which further helped to miniaturize the size of the antenna
Before placing two elements closely, first, polarization and radiation characteristics of a single EMSIW element were investigated because the knowledge acquired would help to achieve high isolation and diversity performances when more than two elements are used for developing a higherorder multiple-input multiple-output (MIMO) antenna
Summary
The 5G new radio (NR) technology has paved the way for enhanced mobile broadband (eMBB) services, which allow the exchange of high data rates [1], and provides an opportunity for developing antennas for such applications, operating in the sub-6 GHz band (i.e., FR1) and millimeter-wave (mmWave) band (i.e., FR2). In order to avoid DN and to achieve high isolation, there is a need to utilize multiple diversity techniques in closely spaced MIMO antennas. These aspects are incorporated in the proposed work. Encouraged by the two-element MIMO antenna results, the concept is extended to detailed simulation study of high-order MIMO antenna, namely, four and twelve-element MIMO antenna for smartphones In this highly space-constrained scenario, closely spaced antennas are strategically placed, and high isolation performance is realized. Advancing the design concept, a diversity investigation of four-element and twelve-element MIMO antennas is carried out, including evaluating channel capacity considering the CBC and Winner II channel models, and a hand mode and SAR study is performed.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
