Publication: Covering THz Gap using photomixers techonologies: arrays and new antenna topologies
Loading...
Identifiers
Publication date
2016-12
Defense date
2016-12-15
Authors
Tutors
Journal Title
Journal ISSN
Volume Title
Publisher
Impact
Export
Abstract
El objetivo de esta tesis es el diseño y construcción de generadores
de señal de terahercios basados en fotomezcladores de bajo coste y que
funcionen a temperatura ambiente. Como se explica en la introducción,
existen muchas aplicaciones potenciales a frecuencias comprendidas entre
los 100 GHz y 1.000 GHz. Propuestas en el campo de la seguridad,
radioastronomía y medicina, entre otros, han sido consideradas y evaluadas.
Algunas de ellas han comenzado a ser explotadas comercialmente,
por ejemplo, en la detección de armas y explosivos ocultos en puestos de
control y seguridad. No obstante, todavía existe un nicho, el de la electrónica
de consumo (comunicaciones, entretenimiento, etc), en el que las
frecuencias de esta banda no son utilizadas por su alto coste.
En una primera parte, se analizan distintos tipos de antenas planares
que son especialmente atractivas para ser integradas con dispositivos
fotomezcladores generadores de terahercios. El efecto de los sustratos
semiconductores en sus propiedades de radiación es analizado en profundidad.
Así mismo, se estudian las principales familias de dispositivos
fotomezcladores.
A continuación, se propone el uso de antenas dieléctricas combinadas
con este tipo de fuentes. Con esto, se pretende evitar el uso de lentes
dieléctricas de alto costo sin reducir drásticamente la cantidad de potencia
de terahercios radiada por la fuente. Se propone un diseño de
antena dieléctrica que permitiría aprovechar el ancho de banda de este tipo de generadores, comenzando en los 50-60 GHz hasta por encima del
terahercio.
Este tipo de antenas dieléctricas ofrece la posibilidad de combinar varios
generadores a fin de cumplir dos objetivos: incrementar la potencia
disponible y escanear electrónicamente en uno o dos planos. Se propone
el uso de nanotubos de carbono para la realización de desfasadores
controlados electrónicamente, componente imprescidible para arrays de
escaneo electrónico.
Finalmente, se estudia la capacidad de este tipo de antenas de actuar
como acoplos de campo cercano en resonadores. Como ejemplo de
aplicación, se propone su uso en un receptor de terahercios cuya sensibilidad,
no limitada por el ruido térmico, llega al límite cuántico, esto es,
la detección de fotones de terahercios.
The objective of this thesis is the design and manufacturing of roomtemperature cost-affordable terahertz sources based on photomixing. As explained in the preface, there are many potential applications for frequencies between 100 GHz and 1 THz. Many of them, specially in the fields of security, radioastronomy, and medicine have been deeply studied and evaluated. Some of them have led to already available commercial products, e.g. in hidden weapons and explosives detection in security controls. Nevertheless, there are many consumer-oriented applications related with communication and entertainment industry that cannot be implemented because of the actual costs of terahertz systems. Firstly, some planar antenna topologies appealing for photomixing sources are shown. The effect of the semiconductor substrates on its radiation properties is theoretically analyzed. Also, the main families of terahertz photomixing sources are described. Secondly, the use of dielectric antennas in combination with photomixing sources is proposed. This allows to reduce costs without a drastic decrement of the radiated power. An utra-wideband design that could allow us to take advantage of the photomixers bandwidth (from 50-60 GHz up to beyond the terahertz) is presented. Thirdly, the combination of many sources in array configurations is proposed. It allows us to accomplish two objectives: increasing the available terahertz power and 1D or 2D beam steering. A novel phase shifter made of carbon nanotubes is presented, since such component is critical for the development of a electronically steerable array. Finally, the use of this family of dielectric antennas as a near field coupler for dielectric resonators is studied. A room temperature photoncounting teraherz receiver is proposed as an example of application. This receiver is limited only by a quantum limit, which gives the theoretical maximum achievable sensitivity for a receiver.
The objective of this thesis is the design and manufacturing of roomtemperature cost-affordable terahertz sources based on photomixing. As explained in the preface, there are many potential applications for frequencies between 100 GHz and 1 THz. Many of them, specially in the fields of security, radioastronomy, and medicine have been deeply studied and evaluated. Some of them have led to already available commercial products, e.g. in hidden weapons and explosives detection in security controls. Nevertheless, there are many consumer-oriented applications related with communication and entertainment industry that cannot be implemented because of the actual costs of terahertz systems. Firstly, some planar antenna topologies appealing for photomixing sources are shown. The effect of the semiconductor substrates on its radiation properties is theoretically analyzed. Also, the main families of terahertz photomixing sources are described. Secondly, the use of dielectric antennas in combination with photomixing sources is proposed. This allows to reduce costs without a drastic decrement of the radiated power. An utra-wideband design that could allow us to take advantage of the photomixers bandwidth (from 50-60 GHz up to beyond the terahertz) is presented. Thirdly, the combination of many sources in array configurations is proposed. It allows us to accomplish two objectives: increasing the available terahertz power and 1D or 2D beam steering. A novel phase shifter made of carbon nanotubes is presented, since such component is critical for the development of a electronically steerable array. Finally, the use of this family of dielectric antennas as a near field coupler for dielectric resonators is studied. A room temperature photoncounting teraherz receiver is proposed as an example of application. This receiver is limited only by a quantum limit, which gives the theoretical maximum achievable sensitivity for a receiver.
Description
Mención Internacional en el título de doctor
Keywords
Antenas, Optoelectrónica, Antennas, Terahertz gap, Optoelectronics