Microstrip band-pass filter with dual tuning of working characteristics

Abstract

Introduction. In recent years, there has been considerable interest in ferrite-piezoelectric composites for dual magnetic and electric field tunable microwave devices, such as resonators or filters. In this article a microstrip band-pass filter manufactured on the base of cylindrical dielectric resonator with tuning element, made from planar structure nonmagnetic dielectric/epitaxial ferrite film/piezoelectric which demonstrates magnetoelectric properties, is considered. The results. Numerical calculations of the microstrip band-pass filter parameters have been done by finite element method in HFSS software suit. The possibility of dual tuning of filter’s three working frequencies by varying the magnetic field and by voltage-induced changes in the magnetostrictive part of uniaxial first-order magnetic anisotropy of epitaxial ferrite film was shown. Proposed device allows low-speed magnetic field tuning in frequency range ∆f ~1 GHz and high-speed electric field tuning in more narrow frequency range ∆f ~150 MHz. Conclusions. Adduced calculations indicate capability of the practical application of the microstrip band-pass filters with dual magnetic and electric field tuning as well as building a wide class of the frequency selective microwave device on the base of composite resonators, comprising DR and ferrite/piezoelectric planar structure. The electrical tuning will lead to low-loss, integrated circuit-compatible, high-speed microwave filters. Miniaturization of the device could be accomplished using permanent magnets to provide the required bias magnetic field.