Thin Film Enabled Tunable Engineered Substrate for Reconfigurable RF and Microwave Applications

This paper presents a methodology in the development of miniaturized and electrically tunable RF and Microwave passives with engineered substrate which has high and electrically tunable effective permeability. The perspective substrate is implemented with multiple layers of 100 nm thick Permalloy (Py) thin film patterns embedded on Silicon substrate, and each Py layer consists of an array of 15μm×40μm Py patterns with 5 μm gaps among them to suppress the magnetic loss. The effective permeability of the single layer and ten layers of Py enabled substrate is tunable by the static magnetic field produced from the applied DC current providing a tunability of 3.3% and 18.8%, respectively. Passives are developed on the proposed engineered substrate with a single layer embedded Py to demonstrate the efficacy of the engineered substrate on the design of arbitrary tunable components. Results show that the developed transmission line-based phase shifter provides continuous 90° phase shift from 0.956 GHz to 1.01GHz, and the center frequency of the bandpass filter shifts from 2.42GHz to 2.56GHz continuously.