Reconfigurable Reflectarrays and Array Lenses for Dynamic Antenna Beam Control: A Review

Advances in reflectarrays and array lenses with electronic beam-forming capabilities are enabling a host of new possibilities for these high-performance, low-cost antenna architectures. This paper reviews enabling technologies and topologies of reconfigurable reflectarray and array lens designs, and surveys a range of experimental implementations and achievements that have been made in this area in recent years. The paper describes the fundamental design approaches employed in realizing reconfigurable designs, and explores advanced capabilities of these nascent architectures, such as multi-band operation, polarization manipulation, frequency agility, and amplification. Finally, the paper concludes by discussing future challenges and possibilities for these antennas.Comment: 16 pages, 12 figure

A review of wideband reflectarray antennas for 5G communication systems

The advancement in the current communication technology makes it incumbent to analyze the conventional features of reflectarray antenna for future adaptability. This work thoroughly reviews the design and experimental features of reflectarray antenna for its bandwidth improvement in microwave and millimeter wave frequency ranges. The paper surveys the fundamental and advanced topologies of reflectarray design implementations which are needed particularly for its broadband features. The realization of its design approaches has been studied at unit cell and full reflectarray levels for its bandwidth enhancement. Various design configurations have also been critically analyzed for the compatibility with the high frequency 5G systems

Robot creativity: humanlike behaviour in the robot-robot interaction

Artificial Intelligence development is mainly directed toward imitat­ing human reasoning and performing different tasks. For that purpose, related software and program solution where artificial intelligence is used have mostly thinking abilities. However, there are many questions to answer in ongoing AI research, especially when we come to the point which is addressing humanlike behaviour and reasoning triggered by emotions. In this paper, we are presenting an interactive installation Botorikko: Machine Create State, which is part of the Syntropic Counterpoints art/research project. We are exposing AI cyber clones to some of the fundamental questions for humankind and challenge their creativity. The robots are trained by using the publications Machiavelli and Sun Tzu and confronted to the crucial questions related to moral, ethic, strategy, politics, diplo­macy, war etc. We are using a recurrent neural network (RNN) and robot-robot interaction to trigger unsupervised robot creativity and humanlike behaviour on generated machine-made content

Three-dimensional printed millimetre wave dielectric resonator reflectarray

Reflectarray antennas have attracted extensive attention due to their low loss, high gain, compact volume, and their excellent abilities to control the radiated beam. The use of dielectric resonators as the reflectarray elements minimises the ohmic loss and the coupling between elements. This study uses fused deposition modelling (FDM) three-dimensional (3D) printing rapidly prototyping a low cost and light-weight dielectric resonator reflectarray. The demonstrated reflectarray is composed of 625 3D printed dielectric resonator elements to control the reflected phase over the reflector surface. The total size is 12 × 12 cm2 and the mass is 67 g. Measurements show that this reflectarray provides 28 dBi gain at 30 GHz when offset fed by a Ka-band horn antenna. This work demonstrates the potential of FDM for millimetre wave (mm-wave) applications. The new 3D printing approach can be deployed for high-gain mm-wave antenna fabrication with significantly reduced labour time and material costs

Penghasilan panduan keselamatan industri bagi kegunaan bakal graduan Kejuruteraan Elektrik Politeknik

Panduan keselamatan industri merupakan satu bentuk bimbingan yang penting kepada pelajar supaya mereka dapat mengetahui dengan jelas tentang amalan dan pengurusan keselamatan keija. Dengan adanya kesedaran dan pengetahuan yang jelas tentang keselamatan keija maka sudah tentu matlamat kemalangan sifar akan mudah tercapai. Untuk perkara ini, satu penyelidikan telah dijalankan untuk menguji tahap pengetahuan pelajar tentang keselamatan industri bagi tujuan untuk menghasilkan sebuah panduan keselamatan industri. Panduan yang telah dihasilkan ini, telah dibuat penilaian mengenai isi kandungan , kebolehlaksanaan dan mesra pengguna kepada pelajar Diploma Kejuruteraan Elektrik di Polileknik Sultan Abdul Halim Muadzam Shah, Jitra, Kedah. Instrumen yang digunakan dalam kajian ini adalah soal selidik. Hasil analisis kajian menunjukkan bahawa nilai purata yang diperolehi daripada penilaian terhadap tahap pengetahuan pelajar adalah sederhana rendah manakala isi kandungan, kebolehlaksanaan dan mesra pengguna pula telah menunjukkan kadar setuju yang agak tinggi. Oleh itu sebagai rumusannya didapati bahawa panduan keselamatan industri yang dihasilkan ini boleh diterima pakai dan boleh membantu meningkatkan pengetahuan pelajar dalam pembelajarannya. Adalah diharapkan agar penyelidikan lanjutan dapat dilakukan terhadap panduan keselamatan industri ini agar ianya dapat dihasilkan kedalam bentuk yang lebih berkesan penggunaannya

Analysis of 3D-printed metal for rapid-prototyped reflective terahertz optics

We explore the potential of 3D metal printing to realize complex conductive terahertz devices. Factors impacting performance such as printing resolution, surface roughness, oxidation, and material loss are investigated via analytical, numerical, and experimental approaches. The high degree of control offered by a 3D-printed topology is exploited to realize a zone plate operating at 530 GHz. Reflection efficiency at this frequency is found to be over 90%. The high-performance of this preliminary device suggest that 3D metal printing can play a strong role in guided-wave and general beam control devices in the terahertz range.Comment: 13 pages, 6 figures, submitted to Optics Expres

MEMS-reconfigurable metamaterials and antenna applications

This paper reviews some of our contributions to reconfigurable metamaterials, where dynamic control is enabled by micro-electro-mechanical systems (MEMS) technology. First, we show reconfigurable composite right/left handed transmission lines (CRLH-TLs) having state of the art phase velocity variation and loss, thereby enabling efficient reconfigurable phase shifters and leaky-wave antennas (LWA). Second, we present very low loss metasurface designs with reconfigurable reflection properties, applicable in reflectarrays and partially reflective surface (PRS) antennas. All the presented devices have been fabricated and experimentally validated. They operate in X- and Ku-bands.Comment: 8 pages; 8 figures; International Journal of Antennas and Propagatio