This thesis is dedicated to characterizing, modeling, and analyzing passive components and interconnects to help solving signal integrity problems occurring in advanced microwave circuits and systems. This type of systems require ultra-wide bandwidth, low dispersion, and low attenuation in the signal transmission to allow high-speed data processing and transmission. In an actual system, however, the transmission of signals from source to destiny suffers attenuation, dispersion and distortion, in addition to high-order effects like resonances, crosstalk, reflection, mismatch, etc., which reduce the bandwidth and the quality of the signals. In this regard, much of the signal power is lost in interconnects, passive devices, and the corresponding interaction with the propagation media as well as with other devices. For this reason, it is very important to understand and properly modeling this type of components in an electronic circuit. The passive elements characterized in this thesis are found at different integration levels. Moreover, different functions are performed by these devices depending on the level at which they are fabricated: interconnection between elements, implementation of matching networks, filters, oscillators, etc. Thus, in order to provide valuable information for circuit designers, the characterization process used in this project was based on the processing of S-parameters measurements, which includes effects corresponding to the intrinsic nature of the passive device, plus the interaction with the surrounding materials. This information allows to represent the performance of passive devices and interconnects by using simple circuits that physically represent their behavior. Bear in mind that using the S-parameters for characterization purposes requires to take into consideration the parasitic effects of the text fixtures necessary to reach the devices under test. In this regard, the impact of these fixtures was also studied in detail in this work. In addition, the potential of S-parameter measurements for characterizing and modeling the properties of the materials used in microwave devices is also explored. This points out the fact that these data is of great value when developing and optimizing circuit and devices since it is possible to analyze the properties even at the level of the fabrication materials.