The intensive research in the fifth generation (5G) technology is a clear indication of technological revolution to meet the ever-increasing demand and needs for high speed communication as well as Internet of Thing (IoT) based applications. The timely upgradation in 5G technology standards is released by third generation partnership project (3GPP) which enables the researchers to refine the research objectives and contribute towards the development. The 5G technology will be supported by not only smartphones but also different IoT devices to provide different services like smart building, smart city, and many more which will require a 5G antenna with low latency, low path loss, and stable radiation pattern. This paper provides a comprehensive study of different antenna designs considering various 5G antenna design aspects like compactness, efficiency, isolation, etc. This review paper elaborates the state-of-the-art research on the different types of antennas with their performance enhancement techniques for 5G technology in recent years. Also, this paper precisely covers 5G specifications and categorization of antennas followed by a comparative analysis of different antenna designs. Till now, many 5G antenna designs have been proposed by the different researchers, but an exhaustive review of different types of 5G antenna with their performance enhancement method is not yet done. So, in this paper, we have attempted to explore the different types of 5G antenna designs, their performance enhancement techniques, comparison, and future breakthroughs in a holistic way.

/pdf/fifth-generation-antennas-a-comprehensive-review-of-design-1q81lfbiqb.pdf

Fifth Generation Antennas: A Comprehensive Review of Design and Performance Enhancement Techniques

Novel soil environment monitoring system based on RFID sensor and LoRa

This communication presents a compact wideband implantable loop antenna with circular polarization (CP) characteristics at 920 MHz industrial scientific and medical (ISM) (902–928 MHz) band and 2.45 GHz ISM band (2.40–2.48 GHz). To widen the impedance bandwidth (IBW) and improve the axial ratio (AR) behavior of the antenna, a reactive impedance substrate (RIS) is exploited. Meandering each arm of the loop makes the antenna compact in size, while the generation of surface wave by the RIS and open-ended configuration of the antenna collectively renders circular polarized wave. The performance of the antenna is analyzed using a single-layer skin model and other existing phantom models. The key feature of the proposed antenna is its dual-band CP behavior, which persists even at the flexion deformation of the human skin. An IBW of 123% with a 3 dB AR bandwidth of 15% and 8.7% is obtained at the planar state of the skin implantable antenna. To validate the simulated results, in vitro measurements were experimentally performed. Also, to find the maximum transmission range of the antenna for biotelemetry communication, the link margin has been analyzed. Finally, to use the antenna inside the biomedical device, the effect of microelectronic components is investigated.

Dual-Band Circular Polarized Flexible Implantable Antenna Using Reactive Impedance Substrate

In this Research article, a circularly polarized Dielectric Resonator Antenna (DRA) that operates in the sub-6 GHz spectrum for future 5G New Radio (5G NR) applications has been proposed. The novel design consists of a Roman Three shaped conformal metal strip excited through a singly fed mechanism. The proposed technique is responsible for circular polarization by exciting the higher-order degenerate modes, i.e., TExδ13 and TEy1δ3.Initially, the roman three shape design produces a narrow 10-dB impedance bandwidth of 10.68% (3.23–3.59 GHz) and axial ratio bandwidth of just 1.47% (3.35–3.41 GHz); to cover the whole 5G NR Bands (n77/n78), the parasitic patch has been introducing at an optimum location on rectangular DRA, such arrangement not only improves impedance matching |S11 | ≤ −10 dB bandwidth by 180 %, i.e., 27.73% (3.26 – 4.35 GHz) but also cover the desired band. Along with this, a noteworthy improvement of ∼ 250% in 3-dB overlapping axial ratio (AR) bandwidth has been attained. In parallel to the Sub-6 GHz 5G NR Bands applications, this antenna can be used for vehicle-to-infrastructure (V2I) and vehicle-to-vehicle (V2V) applications. Finally, the fabricated antenna prototype is tested and offers decent performance in desired parameters. The measured results agree reasonably with simulation results.

Bandwidth enhancement by using parasitic patch on dielectric resonator antenna for sub-6 GHz 5G NR bands application

A low-profile and meandered crossed dipole antenna design for ultrahigh-frequency (UHF) radio-frequency identification (RFID) circularly polarized (CP) tag or handheld reader application is described in this communication. The crossed dipole CP condition is obtained by employing a series power divider meandered at the center of the dielectric substrate, and a surrounding ring which acts as a T-match network guarantees impedance matching. The series power divider alleviates the problem of using a balun when the crossed dipole is fed with a 50 $\Omega $ coaxial cable. A prototype has been manufactured on a $56\times 56\times0.4\,\,\text {mm}^{3}$ FR4 dielectric substrate, and the measurement results show a $S_{11}\le -10$ dB bandwidth of more than 14.4% (865.6–1000 MHz), an axial ratio (AR) ≤ 3 dB bandwidth of 2.8% (906–932 MHz) which can essentially cover the Federal communications commission (FCC) UHF RFID band, and a broadside RHCP peak gain of 1.4 dBic at 919 MHz. When the antenna is connected to an RFID tag chip, excellent read range performance within the whole 902–928 MHz bandwidth has been demonstrated (with maximum values of 7 and 9.9 m when interrogated with a linearly polarized and a CP reader antenna, respectively).

Compact Crossed Dipole Antenna With Meandered Series Power Divider for UHF RFID Tag and Handheld Reader Devices

A multiple-input–multiple-output (MIMO) antenna array for broadband 5G new radio (5G NR) metal-frame smartphone applications is proposed. The MIMO antenna array is realized by loading eight identical antennas (Ant1–Ant8) into the metal frame of the smartphone to form an eight-antenna array for the sub-6 GHz 8 × 8 MIMO system. Each antenna element is a slot antenna type that is composed of an L-shaped open slot and a 50 Ω microstrip feedline, and good impedance matching in the upper frequency band can be achieved by loading a tuning stub to the feedline. The 10 dB impedance bandwidth of the proposed eight-antenna array can cover the 5G NR Bands n77/n78/n79 and wireless local area network (WLAN) 5 GHz band. Besides demonstrating desirable antenna efficiency of 50%–82% and envelope correlation coefficient of 12 dB. At 20 dB signal-to-noise ratio (SNR), the calculated peak channel capacity of the proposed eight-antenna array applied to an 8 × 8 MIMO system is 43.93 b/s/Hz.

Broadband Eight-Antenna Array Design for Sub-6 GHz 5G NR Bands Metal-Frame Smartphone Applications

A planar loop antenna design for ultra-high frequency radio frequency identification (UHF RFID) operating in the 922-928 MHz band is investigated. To achieve compact size of 58.6 × 58.6 mm
 2
 for this loop antenna, the technique of using meandered-loop structure is applied, and by further introducing an open gap into this meandered-loop, good circularly polarized (CP) radiation is also attained. Desirable impedance matching between the meandered-loop antenna and RFID chip is achieved by applying a simple matching stub. Besides exhibiting satisfactory 3-dB axial-ratio (AR) bandwidth of 921-929 MHz and 10-dB impedance bandwidth of 915-942 MHz, good antenna gain of 1.73 dBic and long read range of up to 20.5 m are also demonstrated.

Compact Circularly Polarized Meandered-Loop Antenna for UHF-Band RFID Tag

A simple narrow open-slot antenna design is proposed for smartphone applications. It is constructed by a vertical feedline with two horizontally protruded feeding structures for achieving long term evolution (LTE)/wireless wide area network (WWAN) dual-band operation. To further excite an additional slot mode in the lower operating band, a series capacitor is loaded into one of the protruded feeding structures. For improving the impedance matching for the operating dual-bands, an L-shaped metallic plate attached to the top edge of the ground plane is also applied. Detail configuration and design of the proposed antenna is presented. The simulated and measured return loss is also addressed. From the measured results, good antenna efficiencies of more than 40% are demonstrated across the LTE/WWAN operation in the 698–960 MHz and 1710–2690 MHz bands.

Dual-wideband single open-slot antenna for LTE/WWAN smartphone

A compact loop tag antenna with circularly polarized radiation for the UHF band RFID application is proposed. To achieve compact size and CP radiation, a loop with meander lines is embedded with an open gap. The measured 10-dB impedance bandwidth of the tag antenna is 915–942 MHz, and its 3-dB axial-ratio bandwidth is 921–929 MHz. The antenna gain of about 1.78 dBic and the reading range of larger than 18 m were also demonstrated.

http://ieeexplore.ieee.org/iel7/7362950/7374246/07374320.pdf

Compact circularly polarized loop tag antenna

A simple open slot antenna for the LTE/WWAN operation is presented for the smartphone with a metallic frame. A novel feeding network integrated with a chip capacitor is used to excite the antenna, and the bandwidth of the lower band can be greatly enhanced. Two wide bands for the proposed antenna are easy to adjust and can cover the LTE/WWAN operation in the 698–960 MHz and 1710–2690 MHz bands.

Colin Kuo

Papers

Broadband Eight-Antenna Array Design for Sub-6 GHz 5G NR Bands Metal-Frame Smartphone Applications

Compact Circularly Polarized Meandered-Loop Antenna for UHF-Band RFID Tag

Dual-wideband single open-slot antenna for LTE/WWAN smartphone

Compact circularly polarized loop tag antenna

Simple open slot antenna for LTE/WWAN smartphone with metallic frame