Feed-forward technique to measure S-parameters under jamming CW high power out-of-band signals

Abstract

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.