Fundamental Study on Tunable RF Magnetic Devices Using DC Bias Magnetic Field Generated by Permanent Magnet Film

Abstract

A tunable coplanar resonator using a combination of high-permeability soft magnetic thin film/permanent magnet film was fabricated and evaluated. The magnetic pole based on the remanent magnetization of permanent magnet film, which is controlled by a pulse-current magnetization scheme, generates a dc bias magnetic field in the soft magnetic film. Consequently, the permeability of the soft magnetic film can be controlled by changing the pulse-current magnetization for the permanent magnet film. A scheme to control the permeability of the soft magnetic film is described here, and fabrication and evaluation of the tunable coplanar-resonator are also explained.

A Possibility of Magnetic Field Biasing Tunable Inductive Device Using a Hard Magnetic Film Magnetized by Pulsed-Magnetic Field

“…4 shows a structure of the fabricated CPW shortterminated stub with top and bottom magnetic film layer consisting of soft magnetic FeSiO/SiO 2 granular multilayer film and FeCoSm amorphous hard magnetic film. FeSiO granular film had an intrinsic FMR frequency around 900 MHz and wide FMR linewidth [6], therefore a 20 mm long CPW was designed for operating at several hundred megahertz. Straight signal line consisted of 3 m thick, 50 m wide Cu conductor with 50 nm thick Cr underlayer, which was sandwiched by top and bottom magnetic layer.…”

“…To improve the spatial distribution of bias magnetic field in the soft magnetic film, a divided magnetic film structure composed of short magnetic film segments and air-gap has been introduced [6]. In the fabricated CPW, two different segment length l m of 390 and 657 m, 10 m width air-gap have been introduced, as shown in Fig.…”

Fabrication and evaluation of dispersed-Ag nanoparticles-in-polyimide thin films

“…Therefore, the RF circuits and devices must be smaller and thinner. [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] RF circuits are generally differential input=output circuits that need the common-mode filter (CMF) in order to reduce the common-mode noise generated by unbalance signals. 1,25) The CMF is a common chip device, 26) and its miniaturization is also important in the future.…”

Characterization of Tunable Magnetic Sensor Using Bias Magnetic Field of a Hard Magnetic Film Magnetized by Pulsed-Magnetic Field

“…Figure 5 shows a schematic and dimension of the fabricated tunable MR sensor using bias magnetic field of the hard magnetic film magnetized by the pulsed magnetic field magnetizing method. First, a photo resist pattern with 50 m width air-gap like as lattice pattern and 200 m length segment for hard magnetic film was formed on a glass substrate in order to improve the spatial distribution of bias magnetic field in the soft magnetic film [7]. Then 1 m thick Fe 56.7 Co 36.7 Sm 6.6 (at.%) amorphous hard magnetic film with 1.4 T of M s , and then 50 nm thick SiO 2 film for anti-oxidation barrier layer were deposited by r.f.…”