Genetic Algorithm Optimization of a High-Directivity Microstrip Patch Antenna Having a Rectangular Profile

A single high-directivity microstrip patch antenna (MPA) having a rectangular profile, which can substitute a linear array is proposed. It is designed by using genetic algorithms with the advantage of not requiring a feeding network. The patch fits inside an area of 2.54λ x 0.25λ, resulting in a broadside pattern with a directivity of 12 dBi and a fractional impedance bandwidth of 4%. The antenna is fabricated and the measurements are in good agreement with the simulated results. The genetic MPA provides a similar directivity as linear arrays using a corporate or series feeding, with the advantage that the genetic MPA results in more bandwidth

Contributions to the design of broadband antennas and arrays for base stations for the new generation of mobile communication systems

El objetivo de esta tesis es el diseño de antenas y arrays de banda ancha para estaciones base en las nuevas generaciones de comunicaciones móviles. Los nuevos retos en los sistemas de comunicación tales como el aumento de dispositivos conectados y el Internet de las cosas (IoT), conlleva la aparición de nuevas generaciones de telefonía. Para hacer frente a ese desafío se necesitan nuevas estrategias para optimizar el espectro, aumentar el ancho de banda y las velocidades de transmisión. Aunque algunas técnicas son aumentar la frecuencia de trabajo desarrollando celdas más pequeñas y rápidas, esta tesis se centra en el otro enfoque, extender las bandas de frecuencia utilizadas en la actualidad. Este enfoque tiene algunas ventajas como una mayor penetración ofreciendo mejor cobertura en zonas aisladas, así como la coexistencia de las futuras redes 5G con los estándares 3G y 4G actuales. En una primera parte, se presentan diseños de elementos de antenas planares cumpliendo con los nuevos requisitos. La antena está diseñada y fabricada de una forma rentable y asequible, presentando una topología compacta y completamente plana. La idea principal para la consecución de los objetivos es la inclusión de dipolos acoplados incluidos dentro de la propia antena de forma antipodal para conseguir un diseño compacto y un patrón de radiación estable en toda la banda de funcionamiento. El diseño compacto y de doble polarización se logra en un elemento que trabaja en todo el ancho de banda frecuencial entre 1.427 y 2.69 GHz, la banda que aquí se presenta como Banda Ultra Ancha Extendida (ExtUWB). En segundo lugar, se desarrolla un estudio de diferentes formas de planos de masa o re ectores en el campo cercano del elemento. La inclusi ón de un plano de masa es necesaria para eliminar la radiación trasera y dar forma al haz de radiación para obtener una antena directiva con el ancho de haz deseado que permanezca estable dentro de toda la banda de trabajo. El punto clave a tratar es que el plano de masa o re ector al ser colocado en el campo cercano del elemento produce perturbaciones en el mismo, tanto en la adaptación como en su diagrama de radiación. A continuación, se propone la combinación de dos elementos para cubrir las dos bandas requeridas. El elemento ExtUWB para la banda 1,42 a 2,69 GHz se integra con nuevos elementos para la banda 690 a 960 MHz. Se estudia la integración de los elementos de ambas bandas en un mismo espacio físico para desarrollar una antena de estación base que proporcione cobertura en las dos bandas de forma conjunta. Finalmente, se propone la combinación de elementos en con guraciones de array para las nuevas bandas de 5G con el propósito de ser utilizados como estaciones base. La inclusión en array permite lograr diferentes propósitos: aumentar la directividad, cumplir con los requisitos generales de las estaciones base y obtener exibilidad para diferentes con guraciones de arrays. Se proponen distintos arrays con diferentes objetivos, estos arrays son con gurables para ser utilizados como estaciones base clásicas, pero también formando un nuevo sistema innovador de Massive MIMO con propiedades de haz orientable que no se ha presentado para la banda L hasta ahora.The objective of this thesis is the design of broadband antennas and arrays for base stations for the new generations of mobile communications. The new challenges in the communication systems such as the increase of connected devices, the amount of smart products, and the Internet of Things (IoT), has brought the arrival of new 5G systems. To deal with that challenge, new mobile communication systems need new strategies for optimizing the spectrum, increase the bandwidth and the data rates as it is required. Although some techniques are to increase the working frequency and develop faster and smaller cells, this thesis is focused on the other coliving approach, which is to extend the nowadays mobile communication operating bands. That approach has some advantages as higher penetration with deeper coverage, and the coexistence of future 5G networks with the existing standards. Firstly, some designs of planar antenna element following the new requirements are presented. The antenna is designed and manufactured in a cost-effective and affordable way presenting a compact and fully planar topology. The main idea to obtain the objectives is the inclusion of active embedded dipoles in the antipodal part of the antenna itself to achieve a compact design and a stable radiation pattern within the wide frequency band of operation. Compactness and dual polarized performance is achieved for working in the whole frequency bandwidth between 1.427 and 2.69 GHz, the band that is presented here as the Extended Ultrawideband (ExtUWB). Secondly, a study of different ground plane shapes or reflectors in the element near field is developed. A ground plane is needed to remove the back radiation and shape the radiation beam to obtain a directive antenna with the desired beamwidth that remains stable within the broadband frequency band. The key point to deal with is that the ground plane or reflector placed in the element near field disturbs both the matching and the radiation. Thirdly, the combination of two elements to cover both required bands is proposed. The ExtUWB element for the band 1.42 to 2.69 GHz is integrated with new elements for the band 690 to 960 MHz. Integration of both band elements in the same physical space for developing the base station antenna providing dual band coverage is studied. Finally, the combination of elements in array configurations is proposed for the new 5G bands with the purpose of been used as base stations. It allows to accomplish different goals: increasing the directivity, fufilling the overall base station requirements, and obtaining flexibility for different array configurations. Different arrays are proposed with different objectives, those arrays are configurable for being used as classical base stations, but also as a new innovative system of Massive MIMO with beamsteering properties that has not been presented for the L-band till now.Programa de Doctorado en Multimedia y Comunicaciones por la Universidad Carlos III de Madrid y la Universidad Rey Juan CarlosPresidente: Carlos del Río Bocio.- Secretario: Luis Emilio García Castillo.- Vocal: David González Ovejer

Proceedings of the Second International Mobile Satellite Conference (IMSC 1990)

Presented here are the proceedings of the Second International Mobile Satellite Conference (IMSC), held June 17-20, 1990 in Ottawa, Canada. Topics covered include future mobile satellite communications concepts, aeronautical applications, modulation and coding, propagation and experimental systems, mobile terminal equipment, network architecture and control, regulatory and policy considerations, vehicle antennas, and speech compression

Review of 20 years of research on microwave and millimeter-wave lenses at “Instituto de Telecomunicações”

Starting from a challenge in the early 1990s to develop a highly shaped beam dielectric lens antenna for a pilot 150 Mb/s cellular mobile broadband system operating in the 60-GHz band, several new developments have been accomplished over more than 20 years at Instituto de Telecomunicações [1] in the areas of millimeter-wave shaped dielectric lens antennas and planar metamaterial lenses. We review here a few representative examples with numerical and experimental results, covering applications in mobile broadband communications, radiometry, satellite communications, multigigabit short-range communications, and sublambda near-field target detection.info:eu-repo/semantics/publishedVersio

Two dimensional switched beam antenna at 28 GHz for fifth generation wireless system

Fifth generation (5G) wireless system is expected to enable new device-to-device (D2D) and machine-to-machine (M2M) applications that will impact both consumers and industry. Moreover, for efficient M2M communication, both one dimensional (1-D) and two dimensional (2-D) beam switching is highly needed for high data-rate wireless radio links. A planar array with 2-D beam switching capabilities is highly desirable in 5G system. This thesis proposes a new technique of achieving simple and cost effective 2-D beam switching array antenna at 28 GHz for 5G wireless system. The technique involves lateral cascading of Butler matrix (BM) beamforming network (BFN). However, designing a planar BM at 28 GHz that will allow K-connector is not a trivial issue because the distances between the ports are X/4 electrical length apart. Nevertheless, two branch line coupler (BLC) with unequal ports separation at 28 GHz on a single substrate are designed and applied to design 1-D switched beam antennas based on BLC and 4 * 4 BM. Then two of these antennas are laterally cascaded to achieve 2-D beam switching antenna. This novel concept is the basis for choosing BM BFN in the design. The proposed 1-D array antennas on BLC and BM have wide measured impedance bandwidth of 18.9% (5.3 GHz) and 21.7% (6.1 GHz) and highest gain of 14.6 dBi and 15.9 dBi, respectively. The 2-D switched beam antenna on cascaded BLC has highest realized gain of 14.9 dB, radiation efficiency of 86%, 86.8%, 85.5%, and 83.4% at ports 1 to 4, respectively. The switching range of from -25o to +18° in the x-z plane and from -18o to 24o in the y-z plane, while the 2-D switched beam antenna based on cascaded 4 * 4 BM has switching range of -41o to 43o in the x-z plane and -43o to 42o in the y-z plane with highest realized gain of 14.4 dBi. The proposed antennas have great potentials for 5G wireless communication system applications

Dynamic Capacity Enhancement using a Smart Antenna in Mobile Telecommunications Networks

This work describes an investigation into the performance of antennas for mobile base station applications and techniques for improving the coverage and capacity within a base station cell. The work starts by tracing the development of mobile systems, both in technical and commercial terms, from the earliest analogue systems to present day broadband systems and includes anticipated future developments. This is followed by an outline of how smart antenna systems can be utilised to improve cell coverage and capacity. A novel smart antenna system incorporating an array of slant ± 450 dual- polarised stacked patch elements four columns wide excited by a novel multi-beam forming and beam shaping network has been designed, simulated and implemented. It is found that for an ideal smart antenna array, four narrow overlapping beams, one wide “broadcast channel” beam and right and left shaped beams can be provided. Results are presented for the simulation of the smart antenna system using CST EM simulation software which inherently includes mutual coupling and the effects of a truncated ground plane on the element patterns. The results show some significant changes to the desired set of coverage patterns and various mutual coupling compensation techniques have been reviewed. An improved design technique has been developed for compensating the performance degrading effects of mutual coupling and finite ground plane dimensions in microstrip antenna arrays. The improved technique utilises combination of two previously known techniques: complex excitation weights compensation by inversion of the array mutual coupling scattering matrix and the incorporation of a WAIM (wide angle impedance matching) sheet. The technique has been applied to a novel multi-beam smart antenna array to demonstrate the efficacy of the technique by electromagnetic simulation. In addition, a demonstrator array has been constructed and tested which has yielded a positive conformation of the simulation results. For the developed demonstrator array which provides seven different beams, beams “footprints” have been predicted both for free space propagation and for urban propagation to evaluate the dynamic capacity performance of the smart antenna in a 3G mobile network. The results indicate that sector capacity can be dynamically tailored to user demand profiles by selection of the appropriate beam patterns provided by the novel smart antenna system

Experimental analysis of multidimensional radio channels

In this thesis new systems for radio channel measurements including space and polarization dimensions are developed for studying the radio propagation in wideband mobile communication systems. Multidimensional channel characterization is required for building channel models for new systems capable of exploiting the spatial nature of the channel. It also gives insight into the dominant propagation mechanisms in complex radio environments, where their prediction is difficult, such as urban and indoor environments. The measurement systems are based on the HUT/IDC wideband radio channel sounder, which was extended to enable real-time multiple output channel measurements at practical mobile speeds at frequencies up to 18 GHz. Two dual-polarized antenna arrays were constructed for 2 GHz, having suitable properties for characterizing the 3-D spatial radio channel at both ends of a mobile communication link. These implementations and their performance analysis are presented. The usefulness of the developed measurement systems is demonstrated by performing channel measurements at 2 GHz and analyzing the experimental data. Spatial channels of both the mobile and base stations are analyzed, as well as the double-directional channel that fully characterizes the propagation between two antennas. It is shown through sample results that spatial domain channel measurements can be used to gain knowledge on the dominant propagation mechanisms or verify the current assumptions. Also new statistical information about scatterer distribution at the mobile station in urban environment is presented based on extensive real-time measurements. The developed techniques and collected experimental data form a good basis for further comparison with existing deterministic propagation models and development of new spatial channel models.reviewe