This paper presents a 10-ports, hybrid multiple-input multiple-output (MIMO) antenna system for 5G Smartphone applications. The proposed antenna system comprises two types of antenna modules: (1) multi-band module consists of two identical multiband antenna elements, each antenna element in this module covers the 2G bands (GSM 850/900/1800/1900 MHz), 3G band (UMTS 2100 MHz) and 4G bands (LTE 2300/2500), and (2) single-band module consists of eight identical L shape elements, each antenna element in this module covers the C-band (3400-3600 MHz) for 5G mobile application. The overall dimensions of the proposed antenna system are 150 × 80 mm ² . The proposed antenna system is fabricated and tested. Experimental results show reflection coefficients better than -6 dB and -10 dB for multi-band and single-band modules, respectively, with high isolation levels between the antenna elements in both modules. Moreover, the measured envelop correlation coefficients (ECC) is well below 0.3 and 0.1 for the proposed multi-band and single-bands modules, respectively. In addition, single antenna elements in both modules show good radiation characteristics with maximum peak gain between 2 dBi and 4 dBi. Finally, 43 bps/Hz channel capacity is achieved in the single-band module. With these characteristics, the proposed antenna system can be a good candidate in the modern mobile communication systems.

In this paper, antipodal Vivaldi antenna is designed for 5th generation (5G) mobile communication and Ku-band applications. The proposed designed has three layers. The upper layer consists of eight-element array of split-shaped leaf structures, which is fed by a 1-to-8 power divider network. Middle layer is a substrate made of Rogers 5880. The bottom layer consists of truncated ground and shorter mirror-image split leaf structures. The overall size of the designed antenna is confined significantly to 33.31 × 54.96 × 0.787 (volume in mm${}^3$), which is equivalent to 2$\lambda$${}_o$× 3.3$\lambda$${}_o$× 0.05$\lambda$${}_o$ ($\lambda$${}_o$ is free-space wavelength at 18 GHz). Proposed eight elements antenna is multi-band in nature covering Ku-bands (14.44–20.98 GHz), two millimeter wave (mmW) bands i.e., 24.34–29 GHz and 33–40 GHz, which are candidate frequency bands for 5G communications. The Ku-Band is suitable for radar applications. Proposed eight elements antenna is very efficient and has stable gain for 5G mobile communication and Ku-band applications. The simulation results are experimentally validated by testing the fabricated prototypes of the proposed design.

This paper presents a 4 × 4 multi-input multi-output antenna array for ultra-wideband applications. The single element of the array is comprised of a modified co-planar waveguide-fed double overt-leaf shaped patch radiator. The co-planar ground is optimized to achieve maximum impedance matching in the operating frequency band. The results show that the single antenna element offers an impedance bandwidth of 13.2 GHz starting from 3.2 GHz to 16.7 GHz. It is also observed from the results that the antenna offers good radiation characteristics and acceptable gain for the frequency band of interest. Furthermore, a 4 × 4 MIMO array is designed by utilizing the polarization diversity technique. To improve the isolation performance among antenna elements, a fan-shaped decoupler is introduced on the other side of the substrate, which ensures minimum isolation of 20 dB. Moreover, the proposed MIMO array operates in the frequency range of 2.75–16.05 GHz. The proposed MIMO array is fabricated and measured for the validation of simulation results, and it is observed that both the results are well in agreement.

A MIMO antenna system is designed and presented for sub-6 GHz mobile phone applications. The proposed antenna design consists of six loop-type radiation elements. From the six elements, four elements are placed at the corners of the mobile phone PCB by following pattern diversity configuration, while the rest of the two elements are placed in the center of the PCB. Furthermore, a $50\Omega $ coaxial connector is utilized to feed the antenna elements. From the presented results, it is demonstrated that the elements placed at the edges are resonating at 2.5 GHz, and the center placed elements provide resonance at 3.5 GHz. Moreover, according to S ₁₁ ≤ −6 dB, the impedance bandwidth for both the bands is 790 MHz (2.3-3.09 GHz) and 1.18 GHz (2.99-4.17 GHz), respectively; while for S ₁₁ ≤ −10 dB, the impedance bandwidth for both the bands is noted to be 340 MHz (2.38-2.72 GHz) and 650 MHz (3.17–3.84 GHz), respectively. A gain of more than 4 dBi and >85% radiation efficiency are achieved for the single radiation element. The presented antenna design also provides sufficient radiation coverage supporting different sides of the mobile phone PCB. In addition, the effects of the human hand and head on antenna’s performance are studied and it was observed that the proposed antenna system provides acceptable properties in the data mode and talk mode.

This work presents an eight element array antenna with single layer frequency selective surface (FSS) to obtain high gain. The eight elements are fed by single port. The FSS consists of 14 $\times $ 6 unit cells with one unit cell size is 5 $\times $ 5 mm ² having wideband behavior. The antenna uses Rogers RT Duroid 5880 substrate and giving very wide bandwidth from 20 GHz to 65 GHz, covering millimeter wave 5G bands (including 28 GHz, 38 GHz and 60 GHz). The designed FSS is showing stop band transmission characteristics below −10 dB threshold from 25 GHz to 42 GHz and 59 GHz to 61 GHz. The eight element antenna integrated with the FSS reflector, which results an improvement in the gain level from 12 dB to 15 dB at 28 GHz, from 10 dB to 12 dB at 38 GHz, and from 9.5 to 11 dB at 60 GHz. The dimensions of the antenna are 65 $\times $ 27 $\times $ 0.857 mm ³ . The proposed antenna shows stable gain and directional radiation patterns. The simulation findings are experimentally confirmed, by testing the fabricated prototypes of the proposed antenna system.