|
Descripción
|
|
|---|---|
| The technological developments in the millimeter-wave band have seen a rapid progress recently, owing to the increasing availability of signal-generation sources and detectors at this band, which offer high bandwidths that are of interest for applications such as spectroscopy, security and radioastronomy. Furthermore, the development of technology at this band is expected to play an important role in the creation of new industrial fields that meet society needs. The millimeter-wave band covers the electromagnetic spectrum from 30 GHz to 300 GHz, which corresponds to the wavelength region from 10 mm to 1 mm. This region is a part of a frontier area between electronics and photonics which demands the development of new circuitry that will be able to handle larger power levels and bandwidths in order to cover this technological gap. While the development of technology is an interesting topic itself, the development of technology is more effective when it is considered within the context of a certain application. The requirements of security, biomedical and earth-and-space remote sensing applications demand innovative solutions for which millimeter-wave band radar technology can yield considerable benefits compared to other technologies. To this end, the main goal of this Ph.D. thesis is the development of technology for millimeter-wave radars, particularly for two radars at 94 and 300 GHz for weather monitoring and security applications, respectively. Both applications imply completely different system requirements in terms of antenna subsystem, acquisition times, transmitted power and narrowband/broadband signal generation. The first part of this Ph.D. thesis is focused on the development of technology for a 300-GHz imaging radar designed at the Microwaves and Radar group of the Universidad Politécnica de Madrid in collaboration with the Universidad de Vigo. Active radar sensors at millimeter-wave band are a competing technology for the detection of concealed objects under clothes without the targets being aware of their scanning in risk public areas in contrast to portal systems which increase the system vulnerability. Furthermore, as opposed to X-ray technology, the radiation at millimeter-wave band is non-ionizing and therefore, raise safety concerns. The work carried out in this first part consists of three hardware modifications that improve the radar performance with different alternatives of radar-signal generation, the use of the phase information and the evaluation of polarimetry techniques. The second part presents the design, implementation and characterization of a cloud profiling radar at 94 GHz. Clouds dynamics remain a major source of uncertainty regarding the earth energy balance and global warming, since they contribute to the hydrological cycle and heat and moisture redistribution. This kind of system has a strong interest in meteorology, particularly in the non-precipitating cloud analysis from a commercial and research perspective. | |
|
Internacional
|
No |
|
ISBN
|
|
|
Tipo de Tesis
|
Doctoral |
|
Calificación
|
Sobresaliente cum laude |
|
Fecha
|
23/06/2017 |