A compact four-element multiple-input multiple output (MIMO) antenna is proposed for medical applications operating at a 2.4 GHz ISM band. The proposed MIMO design occupies an overall volume of 26 mm × 26 mm × 0.8 mm. This antenna exhibits a good impedance matching at the operating frequency of the ISM band, whose performance attributes include: isolation around 25 dB, envelope correlation coefficient (ECC) less than 0.02, average channel capacity loss (CCL) less than 0.3 bits/s/Hz and diversity gain (DG) of around 10 dB. The average peak realized gain of the four-element MIMO antenna is 2.4 dBi with more than 77 % radiation efficiency at the frequency of interest (ISM 2.4 GHz). The compact volume and adequate bandwidth, as well as the good achieved gain, make this antenna a strong candidate for bio-medical wearable applications.

This survey addresses the cutting-edge load modulation microwave and radio frequency power amplifiers for next-generation wireless communication standards. The basic operational principle of the Doherty amplifier and its defective behavior that has been originated by transistor characteristics will be presented. Moreover, advance design architectures for enhancing the Doherty power amplifier’s performance in terms of higher efficiency and wider bandwidth characteristics, as well as the compact design techniques of Doherty amplifier that meets the requirements of legacy 5G handset applications, will be discussed.

In this paper, a new high-gain differential-fed dual-polarized microstrip filtering antenna with high commonmode rejection is presented. Two differential pairs of probe feeding ports are utilized to provide differentially exciting signals. The filtering response is achieved by introducing four symmetrical open-loop ring resonator slots on the top layer surrounding the four excitation ports of the patch antenna. The resonators can produce nulls at the low edge of the passband bandwidth with high gain and wide stopband characteristics.Because of the strictly symmetric configuration of the proposed antenna, the design is studied and analyzed only in one polarization configuration. Compared with other presented filtering antenna designs, the proposed design has not only high gain and dual-polarized characteristics but also introduces high efficiency and much lower cross-polarization level due to the differentially driven ports. The filtering antenna is designed, simulated and optimized using computer simulation technology (CST) software and is implemented on a Rogers TMM3 substrate with a relative dielectric constant of 3.45. Also, the antenna has a single layer substrate with a height of 0.035 of the free space wavelength and operating at 3.54 GHz for 5G applications.

No abstract

A very compact microstrip open-loop bandpass filter (BPF) with asymmetric frequency response and covering the 3.4 to 3.7 GHz 5G spectrum is presented in this paper. The planar BPF consists of three trisection open-loop ring resonators with 50 Ω transmission lines for input and output terminals. An attenuation zero of finite frequency is successfully generated on the upper edge of the passband to achieve sharper cut-off frequency for the passband. The realization of the microstrip trisection filters not only reduces the size of the layout but also interduces either positive or negative crosscoupling. The cross-coupling coefficients (Mij) between the poles are optimized to operate at the sub-6 GHz 5G spectrum with appropriate impedance bandwidth. The illustrated BPF is modeled and analyzed using computer simulation technology (CST) tool and is fabricated on a Rogers RO3010 substrate with a relative dielectric constant ( r) of 10.2 and a very small size of 9.5×6×1.27 mm 3 . The simulated and measured results show a good agreement.

A multi-band antenna array is proposed for 5G massive MIMO systems. The presented antenna not only exhibits multi-band operation but also generates the polarization diversity characteristic which makes it suitable for multi-mode operation. Its configuration contains eight modified planar-inverted F antenna (PIFA) elements located at different corners of the smartphone mainboard. For ease integration and design facilitation, the antenna elements and ground plane are etched on the same layer. For S11í10 dB, PIFA elements of the MIMO design operate at the frequency ranges of 2.5-2.7 GHz, 3.4-3.8 GHz, and 5.6-6 GHz covering the LTE 2600, 42/43, and 47 operation bands. Due to the placement of the antenna elements, the proposed design can support both vertical and horizontal polarizations. Fundamental characteristics of the proposed design are investigated. It offers good S-parameters, acceptable isolation, dual-polarized radiation coverage, and sufficient efficiency. In addition, the calculated TARC and ECC results of modified PIFAs are low over the operation bands.

As 5th Generation research reaches the twilight, the research community must go beyond 5G and look towards the 2030 connectivity landscape, namely 6G. In this context, this work takes a step towards the 6G vision by proposing a next generation communication platform, which aims to extend the rigid coverage area of fixed deployment networks by considering virtual mobile small cells (MSC) that are created on demand. Relying on emerging computing paradigms such as NFV (Network Function Virtualization) and SDN (Software Defined Networking), these cells can harness radio and networking capability locally reducing protocol signaling latency and overhead. These MSCs constitute an intelligent pool of networking resources that can collaborate to form a wireless network of MSCs providing a communication platform for localized, ubiquitous and reliable connectivity. The technology enablers for implementing the MSC concept are also addressed in terms of virtualization, lightweight wireless security, and energy efficient RF. The benefits of the MSC architecture towards reliable and efficient cell offloading are demonstrated as a use-case.

No abstract