Flexible Antennas for a Sub-6 GHz 5G Band: A Comprehensive Review

Abstract

The ever-increasing demand and need for high-speed communication have generated intensive research in the field of fifth-generation (5G) technology. Sub-6 GHz 5G mid-band spectrum is the focus of the researchers due to its meritorious ease of deployment in the current scenario with the already existing infrastructure of the 4G-LTE system. The 5G technology finds applications in enormous fields that require high data rates, low latency, and stable radiation patterns. One of the major sectors that benefit from the outbreak of 5G is the field of flexible electronics. Devices that are compact need an antenna to be flexible, lightweight, conformal, and still have excellent performance characteristics. Flexible antennas used in wireless body area networks (WBANs) need to be highly conformal to be bent according to the different curvatures of the human body at different body parts. The specific absorption rate (SAR) must be at a permissible level for such an antenna to be suited for WBAN applications. This paper gives a comprehensive review of the current state of the art flexible antennas in a sub-6 GHz 5G band. Furthermore, this paper gives a key insight into the materials for a flexible antenna, the parameters considered for the design of a flexible antenna for 5G, the challenges for the design, and the implementation of a flexible antenna for 5G.

Characteristics mode analysis based wideband Sub-6 GHz flexible MIMO antenna using a unique hybrid decoupling structure for wearable applications

“…The input power of 100 mW is selected for calculating the SAR at the resonance frequency of 4.1 GHz which is the maximum permissible power that can be fed to the antenna as per the international guidelines for wearable applications [27][28][29]. The dielectric properties of the human body tissues vary with frequencies [4]. The properties of different tissues at 4.1 GHz are given in table 3 which is taken from the ITIS foundation database [30].…”

“…The design of a conformal microstrip antenna for wearable applications is a very challenging task due to the high backward radiation which in turn affects the human tissues [4]. An intense level of electromagnetic (EM) radiation gets absorbed in the human body and is transformed into heat.…”

Antennas for Licensed Shared Access in 5G Communications with LTE Mid- and High-Band Coverage

“…The rapidly growing demands of mobile traffic can be supported by fifth-generation (5G) wireless communication systems [ 1 , 2 , 3 , 4 , 5 , 6 ]. An application of cognitive radio technology named licensed shared access (LSA) has been proposed for 5G mobile communication systems to allow the sharing of spectrum among mobile network operators [ 7 , 8 , 9 , 10 ].…”

Six-element MIMO antenna structure with squared ring structure with multiband and high gain characteristics for C/X/Ku/K band applications

“…Various operating parameters are considered for the GHz frequency applications where MIMO antennas are utilized. These parameters are bandwidth, gain, operating frequency, polarization, radiation pattern and size of the antenna [11,12]. Out of these, operating frequency plays a vital role in the MIMO antenna design.…”