CBL - Campus del Baix Llobregat

Projecte llegit

Títol: Disseny d'un transponder polarimètric de baix cost en banda P

Estudiants que han llegit aquest projecte:

Director/a: CASAS PIEDRAFITA, OSCAR

Departament: EEL

Títol: Disseny d'un transponder polarimètric de baix cost en banda P

Data inici oferta: 20-10-2025     Data finalització oferta: 20-05-2026


Estudis d'assignació del projecte:
    GR ENG SIS TELECOMUN
Tipus: Individual
 
Lloc de realització: Fora UPC    
 
        Supervisor/a extern: Guido Luzi
        Institució/Empresa: CTTC
        Titulació del Director/a: Doctor en Ing. Electrónica y Telecomunic
 
Paraules clau:
Transpoder, Microondas
 
Descripció del contingut i pla d'activitats:
El projecte tracta sobre el disseny i la fabricació d'un transponder polarimètric de baix cost en banda P per a validà el processament de dates adquirits per la futura missió del satèl·lit ESA BIOMASS
 
Overview (resum en anglès):
This Final Degree Project aims to assess the feasibility of a low-cost active transponder operating in P-band for its potential use as a reference target in the context of ESA's BIOMASS mission. The motivation for this work arises from the limitations of passive reflectors at P-band, since the large wavelength requires physically large structures that are difficult to transport, install and maintain in field environments. For this reason, an active architecture is proposed, capable of receiving the SAR signal, conditioning it, amplifying it and retransmitting it back to the satellite, thus generating a high equivalent radar cross section and a stable response in both amplitude and phase.

The methodology followed in this work first consists of a theoretical study of SAR/InSAR systems, active repeaters and the main design parameters involved in this type of device. These include RF gain, radar cross section, phase stability, antenna isolation, linearity, noise figure and group delay. Afterwards, a preliminary selection of commercially available components was carried out for the RF chain, including an RF switch, a low-noise amplifier, a band-pass filter, a power amplifier, a circulator, a directional coupler and auxiliary measurement and control elements. Based on the S-parameters of these components, the behavior of the RF chain was simulated in MATLAB, mainly analyzing the forward transmission, output matching, phase response and associated delays. In addition, a preliminary autonomous power supply system based on a battery, solar panel, MPPT regulator and DC-DC converters was considered.

The obtained results show that the proposed architecture can provide gain levels compatible with the intended purpose of the repeater and that the output matching is reasonably adequate within the analyzed frequency band. However, the work also shows that implementing a fully functional system directly with commercial off-the-shelf components is not completely feasible. Some of the available components do not exactly match the requirements of the system. In particular, the selected band-pass filter has a bandwidth of 20 MHz, which is wider than desired, despite being one of the narrowest commercial options found during the component search. This indicates that, for a real implementation, some parts of the system would need to be specifically designed.

As future work, the design of a dedicated 435 MHz band-pass filter is proposed, together with the development of suitable P-band antennas, the construction of an experimental prototype and the characterization of its frequency response, phase behavior, delay and temperature dependence. It would also be necessary to extend the design towards a fully polarimetric architecture, capable of operating with the HH, HV, VH and VV polarization combinations, in order to better meet the real calibration needs of a mission such as BIOMASS.

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