Survey of various bandwidth enhancement techniques used for 5G antennas

Abstract

Fifth-generation technology is not fully deployed in the world wireless communication till date. Millimeter-wave (mm-wave) band needs to be used due to plenty of available bandwidth and for achieving the goals of 5G such as greater data rate, ultra-high-speed video broadcasting, low latency services, and many more. Wideband antenna is required for 5G applications to access the high speed, low latency Internet services, and ultra-high-definition video streaming. Various bandwidth enhancement techniques have been reported by the researchers for microstrip antennas operating at microwave bands. High link losses, small wavelength, limited coverage, and environmental losses are the major challenges of mm-wave band. To mitigate these issues and satisfy 5G standard, an antenna with wide bandwidth, high gain, narrow steerable beam, high isolation, low side lobe levels, and multiband characteristics is required. Modifications in conventional antenna design techniques are required to achieve broader bandwidth along with stable radiation characteristics, improved gain, and low side lobe levels at mm-wave frequencies. This paper presents the survey of various bandwidth enhancement techniques which has been used in the 5G antennas designed by researchers. Reviews of some wideband 5G antennas with their performance comparisons are also discussed.

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“… ECC of both MIMO configurations is presented at various frequencies in Figure 12B. Optimum value of ECC should be less than 0.5 37‐39 . Figure 12B indicates that ECC is within acceptable limits and less than 0.3 for both configurations at all operating frequencies.…”

“…ECC represents the ability of two antennas to radiate with independent of each other or it provides information about independency of radiation pattern. ECC will be zero in case of one antenna that is horizontally polarized and another antenna that is vertically polarized 37‐41 . ECC can be approximately calculated from scattering parameters using the following Equation (2).…”

“…Diversity gain (DG) indicates the improvement in signal‐to‐noise ratio of multiple‐antenna configuration in comparison to single antenna. Ideally its value should be equal to 10 37‐39 . DG can be calculated using the following Equation (3).…”

“…Total active reflection coefficient (TARC) represents the effective radiation of all the power with least reflections and it characterizes the frequency bandwidth and radiation properties of MIMO systems. It can be calculated using ratio of square root of total incoming power at the ports to the square root of total unwanted reflecting power 39 . It represents the overall return loss of MIMO antenna 37,39 .…”

“…Channel capacity loss represents the loss in transmission in bits/sec/Hz. It provides the information about the limit upto which lossless communication can be possible 37‐39 . It can be calculated using Equations (5) to (10).…”