Tunable RF components are key elements in frequency reconfigurable and multifunctional systems. However there are technological barriers to achieve miniaturized fully electrically tunable RF components. This paper provides a unique design methodology in developing electrically tunable RF devices from the integration of ferromagnetic (Permalloy) and ferroelectric thin films. Permalloy thin film has been patterned in nanometer scale to improve its ferromagnetic resonance frequency for RF applications. A tunable transmission line with simultaneously variable inductance and capacitance density is developed, and measured results show that a fixed phase shift can be achieved from 2GHz to 1.55 GHz with the application of DC current and voltage. A center frequency tunable bandpass filter has also been developed with the application of Py thin film. In addition, engineered substrate implemented with embedded Permalloy and PZT patterns has been proposed which provides both electrically tunable equivalent permeability and permittivity; arbitrary tunable RF components are achievable on the proposed substrate combined with the state-of-art tunable techniques. t Times New Roman Bold font. An example is shown next.