X-Parameter Characterization of TC SAW Filters with Enhanced Dynamic Range

Increasing the integration of radio frequency frontend modules for mobile communication devices results in rising power densities within the components. Additionally, advanced communication techniques demand for more frequency bands to be supported. As a result, the probability of significant nonlinear emissions disturbing adjacent channels increases, and accurate modeling of the device's response is required. The X-parameter-based modeling approach can be applied to this problem. In this paper, a measurement setup, which is based on a nonlinear vector network analyzer, is utilized in order to characterize a surface acoustic wave (SAW) filter. Due to the low power levels of the generated higher order harmonics and the demand for a power sweep, a high dynamic range (DR) is required. The application of frequency selective attenuators enables an increase of the effective DR by more than 40 dB. Based on this improved measurement setup, single-tone and two-tone X-parameter models of the SAW filter are created and evaluated for their ability to predict intermodulation distortion (IMD). Classic, scalar IMD measurements are used as a reference for the assessment of capabilities and limitations of both X-parameter approaches.