Design, fabrication, and measurement of efficient beam-shaping reflectors for 5G mm-wave applications

Karaova, Gökhan Çağlayan
In this study, an optimization procedure to design corrugated passive metallic reflectors for the fifth-generation millimeter wave (5G mm-wave) applications, as well as the fabrication and measurement of the designed reflectors, are presented. Such reflecting surfaces can be used as passive repeaters in both indoor and outdoor applications to change the field coverage by redirecting incident beams into desired directions with controllable power distributions. The design procedure includes a heuristic optimization method (genetic algorithms (GAs)) and full-wave electromagnetic analyses. For efficient and effective optimization of complex geometries, a multigrid approach is used. In this approach, the number of surface representation points is gradually increased in the course of an optimization to reach the best designs via a dynamic process from coarse shaping to fine tuning. Multilevel fast multipole algorithm (MLFMA) is used for the required full-wave electromagnetic analyses by reducing the computation time substantially without deteriorating the accuracy. The optimized geometries are fabricated using a three-dimensional (3D) printing method that enables low-cost and adaptive fabrication. The fabricated 3D prints are coated with a low-cost conductive paint to obtain the final reflectors. Measurements are performed using a Naval Radio Lab arch (NRL arch) and in a free-space setup. The measured results are in good agreement with the simulations, demonstrating the success of both the design procedure and the designed reflectors as efficient 5G components. The designed reflectors provide solutions to the demand for low-cost and energy-efficient signal repeaters needed in 5G mm-wave mobile communication. Thanks to the adaptive design procedure and the use of 3D printing technology, the proposed types of reflectors can be realized and implemented for diverse configurations and alternative scenarios, where the distribution of the signal needs to be controlled in free space. Finally, the designs presented in this study have large bandwidths, while they are also scalable for alternative frequency ranges.


Design and Simulation of Passive Reflecting Surfaces for 5G Applications
Karaova, Gokhan; Ergül, Özgür Salih (2021-01-01)
Design and simulation of passive reflectors to be used in 5G applications are presented. An optimization environment is constructed based on genetic algorithms (GAs) and a full-wave solver to obtain compact reflectors that possess various reflection characteristics in accordance with given design specifications. In addition to their triangulated models for simulations, reflectors are represented by Bezier surfaces on the optimization side to reach smooth designs that are suitable for fabrication. A multigri...
Cetin, Ramazan; Erturk, Ozan; Akın, Tayfun (2018-09-14)
This study presents design, analysis, optimization, and fabrication of umbrella structures as an efficient quarter wave absorber within the Long Wave Infrared (LWIR) range for uncooled IR detectors. Both the effect of the ni-chrome (NiCr) layer and effect of varying pixel pitch sizes on the IR absorption performance of the umbrella structures are examined. An average of 96% absorption is measured for the optimized case within the LWIR range.
Design of a GaN Based Integrated Modular Motor Drive
Uğur, Mesut; Keysan, Ozan (2018-10-25)
In this study, design procedure of an Integrated Modular Motor Drive (IMMD) is presented focusing on high power density. The design is based on a permanent magnet synchronous motor (PMSM) and GaN FETs. Fractional slot concentrated windings are used on the stator. Slot/pole combination and winding configuration is selected based on having low cogging torque and high winding factor. An extended motor drive inverter topology is proposed where 2-level voltage source inverters are connected both in series and pa...
Design of a tubular switched reluctance linear generator for wave energy conversion based on ocean wave parameters
Mendes, R. P. G.; Calado, M. R. A.; Mariano, S. J. P. S.; Cabrita, C. M. P. (2011-09-10)
This work presents a procedure for the design and analysis of a linear tubular switched reluctance generator for wave energy conversion. The generator is meant to be applied to a direct drive wave energy converter, namely a point absorber. The device is modeled according to wave climate conditions at Esposende site in the Portuguese coast. The procedure starts with statistical analysis of the local random ocean behavior in order to determine most likely values of occurrence for the wave parameters in questi...
Performance Calculation of SR Motors for Optimum Design and a Washing Machine Application
Ertan, Hulusi Bülent (2008-09-09)
This paper aims to develop an approach for performance calculation of an SR motor, which is suitable for use within mathematical design optimization. For this reason the requirement is to develop procedures, which are both accurate and fast. The procedures adopted here rely on flux-linkage-current-position curves of the motor. A series of tests are carried out on a test motor. The results are compared with estimations from the developed algorithms. It is shown that the current waveform, torque-speed curve, ...
Citation Formats
G. Ç. Karaova, “Design, fabrication, and measurement of efficient beam-shaping reflectors for 5G mm-wave applications,” M.S. - Master of Science, Middle East Technical University, 2021.