Projecte llegit
Títol: Feed-forward technique to measure S-parameters under jamming CW high power out-of-band signals
Director/a: GONZÁLEZ ARBESU, JOSÉ MARIA
Departament: TSC
Títol: Feed-forward technique to measure S-parameters under jamming CW high power out-of-band signals
Data inici oferta: 19-01-2017 Data finalització oferta: 21-01-2017
Estudis d'assignació del projecte:
MU MASTEAM 2015
| Tipus: Individual | |
| Lloc de realització: EETAC | |
| Segon director/a (UPC): COLLADO GÓMEZ, CARLOS | |
| Paraules clau: | |
| Microwave devices, Feedforward, S-parameteres, High-power, Vector modulator, Cancellation | |
| Descripció del contingut i pla d'activitats: | |
| Microwave devices behave differently as expected under the
presence of jamming continuous-wave high power out-of-band signals. In these cases, measuring the scattering parameters is difficult and requires a specific set-up and/or a PNA. Set- ups are complex and include booster amplifiers, directional couplers, attenuators, hybrids, and eventually filters. A feedforward technique can be used to cancel the jamming signal and consequently increase the sensitivity of the vector analyzer in charge of measuring the S-parameters. This technique requires a vector modulator. The jamming signal is split in two paths being one of them the input of a vector modulator (VM). The magnitude and phase of the VM output is controlled in order to cancel the jamming signal after being combined with the other path. The magnitude and phase of the VM output is found by means of an iterative algorithm. In this work, both the feedforward set-up and the cancellation algorithm are discussed. The technique (set-up and algorithm) are tested by characterizing some microwave devices. |
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| Overview (resum en anglès): | |
| In recent years, high-power radio frequency (RF) devices have become increasingly common due in part, to the high-speed telecommunications industry. The evolution of mobile devices drives to the use of wireless applications which will require different work frequencies and therefore the implementation of new and miniaturized devices.
Moreover, passive intermodulation requirements at high-power levels, power handling of transmitting filters, thermal stability behaviour of duplexers, interference blockers, etc. are some examples of the increasing interest in characterizing passive devices such when they are driven by high power signals. Nowadays, there exist devices that use the above-mentioned power requirements. For example, a radar protection circuit of jamming signals incorporating frequency-selective auto-limiting devices must keep the low-signal performance while dealing with high power signals. The high-power components used in these applications must be characterized for both linear and nonlinear operation. Therefore, complex calibration procedures must be done and the calibration standard must be able to handle the power without changing their parameters or alternatively, using previously characterized power standards. Feed-forward techniques have been shown very useful to measure passive intermodulation (PIM) without using narrowband filters. The objective in PIM measurements is cancelling the high-power tone before going into the spectrum analyzer. Since no filters are required, there are no restrictions between the separation of tones and the system is not-specific to a given narrowband bandwidth. This master thesis is focused in the study of the interference problem in high-power transmitted signals and out-of-band transmissions through the design of different feed-forward cancellation algorithms with the aim of measure and characterize high-power components as well as study the nonlinear behaviour caused by thermal effects of Bulk Acoustic Wave (BAW) resonators due to the use of high-power signals. |
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