Design and fabrication of low-cost ferrite circulators

Webb, David J.

doi:10.1109/euma.1995.337153

Cited by 10 publications

(3 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In our laboratory, we have focused our researches on the realization of an integrated circulator working at 77 GHz, which is a working frequency for military applications. But at this frequency, a paper published by Denis C. WEBB explains that the films must have a thickness at least equal to 50 m to minimize insertion losses in the circulator 2 (Fig. 1).…”

Section: Introductionmentioning

confidence: 97%

Properties of barium hexaferrite thick films deposited by electron beam evaporation

Vérité¹,

Valetas²,

Bessaudou³

et al. 2005

Journal of the European Ceramic Society

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 97%

Properties of barium hexaferrite thick films deposited by electron beam evaporation

Vérité¹,

Valetas²,

Bessaudou³

et al. 2005

Journal of the European Ceramic Society

View full text Add to dashboard Cite

“…The technology used to deposit the Ba-M ferrite is electron beam evaporation which allows high deposition rates [2]. Indeed, acceptable coating thickness for circulator operating at lower millimeter wave frequencies should approach 100 µm to obtain low losses [3]. The growth rates obtained are typically in the 1 to 40 µm per hour range depending on deposition parameters.…”

Section: Introductionmentioning

confidence: 99%

Hard Ferrite Films Prepared by Electron Beam Evaporation for Microwave Applications

Wane

Cosset

Bessaudou

et al. 2000

Interface Controlled Materials

View full text Add to dashboard Cite

In classic circulators, exterior permanent magnet is used for biasing the ferrite. In the MMICcompatible circulators, self-biased ferrites are needed [1]. To be used as film, the permanent magnet material must have good properties at microwave frequencies. This particular ferrites are hexaferrites and the most commonly used are barium and strontium ferrites.This work deals with the study of barium hexaferrite films high rate deposition. The bulk material deposited has the formula BaFe 12 O 19 . The films are grown on silicon (100) substrate. To increase adhesion and minimise cracks on the ferrite films, we deposit first one or two thin (≈ 1 µm) metallic films. A preliminary study shows that ferrite films deposited on a gold and palladium alloy underlayer are more adhesive than those on silicon. Secondly we use metallic underlayer more compatible with microwave frequencies. It can be Gold (Au), Copper (Cu), Gold on Titanium (Au/Ti) or Copper on Titanium (Cu/Ti). The metallic layers play also a role of ground plane in the circulator circuit (see figure 1). The Ti layer is used to improve adhesion of Au or Cu layers on silicon (100) substrate. The metallic layers are grown by dc cathodic magnetron sputtering. Figure 1 : Circulator's topologyThe technology used to deposit the Ba-M ferrite is electron beam evaporation which allows high deposition rates [2]. Indeed, acceptable coating thickness for circulator operating at lower millimeter wave frequencies should approach 100 µm to obtain low losses [3]. The growth rates obtained are typically in the 1 to 40 µm per hour range depending on deposition parameters.The growth parameters studied are deposition rate, oxygen flow, substrate temperature and post-deposition annealing. The effect of these parameters on crystallographic structure, magnetic properties, morphology and composition has been investigated.The crystallographic structure is analysed by XRD with a SIEMENS generator equipped with a goniometer. The saturation magnetisation (4πM s ), coercive field (H c ) and remanent ratio (RR) are measured using a hysteresismeter M2100 with a DC magnetic field applied in the film plane. Morphology and composition of the deposited films are measured by Scanning Electron Microscopy (SEM) equipped with a X-Ray Dispersion analysis system. 5 : circuit's ground plane 4 : substrate 3 : circulator's ground plane 2 : ferrite film 1 : top armature Interface Controlled Materials. Edited by M. Rühle and H. Gleiter

show abstract

“…Due to their high magnetocrystalline anisotropy, they exhibit a ferromagnetic resonance at mm-wavelengths, while, at the same time, they are magnetically self-biased. The most suitable form of barium ferrite for mm-wave applications is magnetically oriented thick films [6]. Several techniques have been used to prepare such films, e.g.…”

Section: Introductionmentioning

confidence: 99%

Preparation and characterisation of magnetically ordered columnar structures of barium ferrite particles

Kolev

Lisjak

Drofenik

2011

Journal of Experimental Nanoscience

View full text Add to dashboard Cite

In this study, we report on the columnar structures of barium ferrite particles that were prepared from water suspensions by applying a magnetic field during drying. Commercial barium ferrite (BaFe 12 O 19 ) monodomain particles were used, and the surfaces of the particles were treated with an organic surfactant to reduce their agglomeration. The columnar structures were obtained by drying the water suspensions of BaFe 12 O 19 particles on Al 2 O 3 substrates under an applied magnetic field of 1 T. After the degradation of the organic components, the samples were sintered at 1350 C. X-ray powder diffraction, scanning electron microscopy and magnetic measurements were used to characterise the samples. When the magnetic field was applied perpendicularly to the sample plane, the as-deposited sample exhibited a higher coercivity (H c ¼ 5434 Oe) and a higher squareness ratio (SQR ¼ 0.76) than the sintered sample (H c ¼ 625 Oe, SQR ¼ 0.58). However, the sintered sample showed a higher anisotropy of the magnetic behaviour than the as-deposited sample.

show abstract

Design and fabrication of low-cost ferrite circulators

Cited by 10 publications

References 14 publications

Properties of barium hexaferrite thick films deposited by electron beam evaporation

Properties of barium hexaferrite thick films deposited by electron beam evaporation

Hard Ferrite Films Prepared by Electron Beam Evaporation for Microwave Applications

Preparation and characterisation of magnetically ordered columnar structures of barium ferrite particles

Contact Info

Product

Resources

About