Análisis y diseño de antenas Microstrip con polarización circular y sentido de giro seleccionable en las que se combinan dos técnicas que permitan reducir su tamaño y mejorar su ancho de banda de impedancia y de relación axial

Abstract

Since ancient times, human beings have sought a way to communicate remotely; In fact, thanks to the invention of writing, it has been something that has been achieved for thousands of years; However, except for very reduced forms of communication such as smoke signals, instantaneous communication was not achieved until the mid-19th century with the invention of the telegraph, which has multiple drawbacks and limitations due to its own nature; Later, thanks to the work of Maxwell, Helmholtz and many other scientists, electromagnetic waves were discovered, through which it was stipulated that a simpler way of communicating instantly would be achieved without the need for a conductive element in between; Then, thanks to the work of Hertz, a way to produce them was found and later, thanks to the work of Marconi and Popov, the first radio links emerged through the invention of antennas. Since then, communications systems have evolved considerably, going from wireless telegraphy at the beginning of the 20th century to the mobile telephony used today, in which antennas continue to be the element that connects both ends of the radio link. However, as expected, the needs in telecommunications systems have changed and will continue to change constantly, and with this the antennas also change to meet new needs. Currently with the evolution of the mobile communications system, that is, with the incorporation of 5G; The aim is to increase the browsing speed of users, thereby making the large-scale implementation of several emerging technologies a reality (augmented reality, internet of things, video game services from the cloud, etc...) [1], which is why we seek to implement new types of antennas or improvements in existing antennas; such as, for example, and in the case of this work, improving the scale and bandwidth of antennas implemented in Microstrip. One of the virtues of communications links based on transmission lines, whether conductive or dielectric as in the case of optical fiber, is their low link losses because, unlike a radio link, all the energy transmitted from one of the nodes of the link to the opposite node is confined; while the energy transmitted by a terminal node constituted by an antenna is radiated into space in either a uniform (omnidirective) or disparate (directive) manner, which suggests that in the radio link, all the transmitted energy is distributed over the surface equidistant covering the radiating element; while in the link based on a transmission line All the transmitted energy is distributed over the thread that makes it up. In addition to what has been said above, in a radio link there are many other types of losses in addition to free space losses (losses specifically associated with the propagation of the transmitted energy over the equidistant surface that covers the radiating element as described above). previously); These losses are associated with the environment over which the energy is radiated (multipath losses), the medium through which the radiated electromagnetic waves propagate (absorption losses) and the orientation of the antenna that constitutes the terminal node of the receiver. of the radio link with respect to the orientation of the transmitter antenna (polarization losses); However, although the free space losses are a function of the frequency at which the radio link operates and therefore, there is control over them to the extent possible, the other types of losses except the losses due to polarization, are not based on any controllable parameter of the radio link, such as the radiation parameters of the antennas that constitute it, which suggests that every radio link seeks to minimize polarization losses, something that is obtained by properly orienting the radio-link antennas, but there are various environments in which a specific orientation cannot be guaranteed in the antenna of one of the radio-link nodes, such as, for example, in mobile telecommunications, where It seeks that the user can operate their device regardless of the orientation given to it, which is why it is necessary to compensate for polarization losses by choosing a type of polarization that allows them to be independent of the orientation of one of the radio antennas. -link with respect to the one possessed by the other, and this is, circular polarization