One of the most important developing fields is that of digital communication. This is due to the demand for an increasingly higher speed in the exchange of information, which is presently growing at an exponential rate. In fact, considerable efforts have been made towards the realization of low-power miniaturized radio frequency components. However, issues related to design and fabrication of efficient, ultra-compact, and easily integrate-able microwave components appear to be challenging. Many unit cells are needed in order to achieve high efficiency components, such as filters and couplers, whose dimensions are comparable or larger than a single wavelength cycle. However, during the past decade, metamaterials, a novel class of artificial materials, have become a field of active research in physics and engineering. These metamaterials offer unique electrodynamic properties, which are neither available in any natural material nor observable in the materials presently used in state-of-the-art technology. Furthermore, a metamaterials unit cell is much smaller than the wavelength of reference. The main objective of my dissertation was to design and realize new resonator structures to meet the challenges of simple, high performance, and miniaturized microwave circuits as well as terahertz components for filtering and sensing applications. First of all, I suggested a series of novel structures for filter applications. They consist of only a single metal layer, an approach which I suggested for the first time worldwide. Later on, I realized more advanced miniaturized resonators based on the same idea.