In this study, a multi‐polarised millimetre‐wave (mm‐Wave) base station operating at 28/38 GHz is introduced for future fifth generation (5G) mobile communication networks. The proposed station employs 32‐element array antenna distributed in upside conical frustum configuration (UCFC) to synthesise multi‐beam patterns adopting directivity and polarisation control. First, the design of dual‐band circularly polarised antenna element at 28/38 GHz is discussed. The measured results show that the designed antenna element has a reflection coefficient less than −23 dB with a realised antenna gain of 8 dBi, on average, in the assigned frequency bands. Based on the designed antenna element, the antenna array performance is studied in terms of gain, radiation efficiency, reflection coefficient, and coverage efficiency. The results are compared with those obtained from 32‐element structured in an octagonal prism configuration (OPC). For antenna design parameters and multi‐beam pattern synthesis, a modified version of hybrid gravitational search algorithm and particle swarm optimisation is proposed. It is found that, the introduced UCFC outperformed the OPC by 19.8%. Moreover, distributing the antenna array in UCFC improved the convergence by 21.7% compared to OPC.
Here, a new design of phased‐array antenna for future fifth‐generation mobile phone applications is presented. The proposed phased array consists of 12 dual‐band circularly polarised antenna elements at 28/38 GHz used to form a linear array in the edges region (top‐side, right, and left sides) on a mobile phone circuit board. The measured and simulated results show that the designed antenna element has a reflection coefficient less than −15 dB in the assigned frequency bands of 28/38 GHz with a realised antenna gain of 7.68 and 7.73 dB, respectively. Furthermore, the performance of the array antenna package in the vicinity of user's head–hand has been investigated in this study at different scenarios. The designed array antenna achieved good matching impedance with high isolation between the array elements. Moreover, an acceptable realised gain of 16.85 dB on average with an axial ratio <3 dB is obtained in the entire operation bands. Lastly, the metrics of total scan pattern, coverage efficiency, and user shadowing are investigated. It is found that the proposed phased‐array antenna has good 3D beam‐steering characteristics, which makes it suitable for millimetre‐wave 5G mobile applications.
Hyperthermia therapy has recently become one of the primary treatment principles due to its prominence and success in curing deep-rooted malignancies, especially for breast tumors. Therefore, a proposed multi-resonance applicator (MRA) was designed and investigated in this study and compared with the performance of a single resonance applicator (SRA). The MRA applicator includes a set of 35 antenna elements operating simultaneously in different frequency bands. This is accomplished by applying a modified version of the gravitational search algorithm hybridized with particle swarm optimization to design the antenna element and focusing the heat on the tumor. Machine learning was used to build antenna elements operating in different frequency bands. Several scenarios considering realistic thermal and dielectric breast properties with a single tumor of different volumes and positions are addressed to evaluate the applicator's performance and capability. The results showed the capability of the proposed MRA applicator to use a microwave power of 60 watts to elevate the temperature of the tumor to over 42.5° C with better performance indicators than SRA. The suggested methodology of using MRA can be considered to treat successfully other malignancies in different organs, such as brain, liver and larynx tumors.
INDEX TERMSAdaptive beamforming, hyperthermia treatment, machine-learning, optimization techniques.
Abstract-In this paper, the interaction of a planar inverted-F antennas array, mounted on a mobile handset, with a human hand-head phantom is investigated in the 1.9 GHz band. The hybrid approach involving the particle swarm optimization (PSO) and Nelder-Mead (NM) algorithm is considered to optimize the complex excitations of the adaptive array elements in a mutual coupling environment for different beamforming synthesis. Firstly, the effect of the human handhead on the handset radiation characteristics is studied. Then, the spatial-peak specific absorption rate (SAR) values of 2-and 4-element PIFA arrays for mobile handset in the vicinity of a human handhead are evaluated numerically for different scenarios. The antenna is analyzed completely using finite difference time domain (FDTD) method while the interaction is performed using the CST Microwave Studio software.
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