Deployable Helical Antennas for CubeSats

This paper explores the behavior of a self-deploying helical pantograph antenna for CubeSats. The helical pantograph concept is described along with concepts for attachment to the satellite bus. Finite element folding simulations of a pantograph consisting of eight helices are presented and compared to compaction force experiments done on a prototype antenna. Reflection coefficient test are also presented, demonstrating the operating frequency range of the prototype antenna. The helical pantograph is shown to be a promising alternative to current small satellite antenna solutions

Design, realisation and evaluation of a liquid hollow torso phantom appropriate for wearable antenna assessment

This paper is a postprint of a paper submitted to and accepted for publication in IET Microwaves, Antennas & Propagation and is subject to Institution of Engineering and Technology Copyright. The copy of record will be available at the IET Digital Library.This paper examines the design, realization and evaluation of a lightweight and low cost hollow oval cross-section torso phantom appropriate for wearable antenna performance assessment. The phantom consists of an empty inner space (hollow) surrounded by a shell with double plastic walls between which there is a tissue simulating liquid. The phantom’s plastic shell is made of a low loss cast acrylic and the liquid is a commercially available one with properties calibrated for the frequency range of 2 - 6 GHz. The proposed phantom is compared, through simulations, with a full liquid torso phantom and a heterogeneous anthropomorphic voxel phantom. Additionally, the fabricated phantom is compared with human bodies and a homogeneous anthropomorphic solid phantom, through measurements. The phantom performance is tested in terms of electric field distribution of a wearable antenna on its surface and the path loss between two wearable antennas, on either side of the phantom. It is proved that the hollow phantom performance approximates the full liquid phantom when an RF absorbing material is placed in the central hollow region. The phantom performance in terms of S11 wearable antenna measurements is evaluated and found in good agreement with real human bodies in the examined frequency range (2 - 6 GHz). The far field wearable antenna performance of the proposed phantom shows deviation in gain less than 1.5 dB, compared with anthropomorphic phantom

Radiation pattern reconfigurable fm antenna

In this work, a radiation pattern reconfigurable antenna design using compact printed spiral monopoles that operates at 102 MHz is reported. The proposed antenna changes its radiation behaviour that responds towards a desired direction with the use of RF switches. The antenna is printed on a 76.6mm × 50mm PCB layer providing more than 20MHz bandwidth at -10 dB threshold and is easily fabricated with low manufacturing cost. The antenna was also simulated on 500mm × 500mm ground plane that represents the roof top of a vehicl

Angular dependence of the radiation power of a Josephson STAR-emitter

We calculate the angular dependence of the power of stimulated terahertz amplified radiation (STAR) emitted from a $dc$ voltage applied across a stack of intrinsic Josephson junctions. During coherent emission, we assume a spatially uniform $ac$ Josephson current density in the stack acts as a surface electric current density antenna source, and the cavity features of the stack are contained in a magnetic surface current density source. A superconducting substrate acts as a perfect magnetic conductor with $H_{||,ac}=0$ on its surface. The combined results agree very well with recent experimental observations. Existing Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ crystals atop perfect electric conductors could have Josephson STAR-emitter power in excess of 5 mW, acceptable for many device applications.Comment: 3 pages 3 figure

RFID en el servicio bibliotecario de la UTM

The central library of the Technical University of Manabí (UTM), offers the service of electronic equipment loans (laptops and tablets), in which theft has been presented. In the present article the integration of identification technologies through a web application is exposed. To do this, the requirements were raised, systems analysis and identification technologies were analyzed. Based on the study of art, the development methodology, programming languages, tools and technologies applied in the solution were described, the system architecture was designed with visual / audible alarm, the integrating system was developed and implemented and finally functional tests were carried out. As a result, it was evidenced that using bar code and RFID technology in the library service, there is better control of the entry and exit of electronic equipment, preventing any attempt at theft, and the university and general community receive a quality and speedy service.La biblioteca central de la Universidad Técnica de Manabí (Ecuador)brinda el servicio de préstamos de equipos electrónicos (portátiles y tabletas), en el que se han presentado hurtos de los mismos. En este artículo se expone la integración de RFID a través de una aplicación web. Para ello, se realizó el levantamiento de requerimientos, análisis de sistemas y de tecnologías de identificación, tomando como base el estudio del arte se describió la metodología de desarrollo, lenguajes de programación, herramientas y tecnologías aplicadas en la solución, se diseñó la arquitectura del sistema con alarma visual/sonora, se desarrolló e implantó el sistema integrador y, finalmente, se ejecutaron pruebas de funcionamiento. Como resultado se evidenció que al utilizar tecnología de código de barras y RFID en el servicio bibliotecario existe un mejor control de entrada y salida de los equipos electrónicos, previniendo de cualquier intento de hurto; a su vez, la comunidad universitaria y general recibe un servicio de calidad y rapidez

Near-field optical power transmission of dipole nano-antennas

Nano-antennas in functional plasmonic applications require high near-field optical power transmission. In this study, a model is developed to compute the near-field optical power transmission in the vicinity of a nano-antenna. To increase the near-field optical power transmission from a nano-antenna, a tightly focused beam of light is utilized to illuminate a metallic nano-antenna. The modeling and simulation of these structures is performed using 3-D finite element method based full-wave solutions of Maxwell’s equations. Using the optical power transmission model, the interaction of a focused beam of light with plasmonic nanoantennas is investigated. In addition, the tightly focused beam of light is passed through a band-pass filter to identify the effect of various regions of the angular spectrum to the near-field radiation of a dipole nano-antenna. An extensive parametric study is performed to quantify the effects of various parameters on the transmission efficiency of dipole nano-antennas, including length, thickness, width, and the composition of the antenna, as well as the wavelength and half-beam angle of incident light. An optimal dipole nanoantenna geometry is identified based on the parameter studies in this work. In addition, the results of this study show the interaction of the optimized dipole nano-antenna with a magnetic recording medium when it is illuminated with a focused beam of light