Microwave ferrites, part 2: passive components and electrical tuning

Microwave ferrites, part 1: fundamental properties

“…Such antisymmetrical condition of ferrites is necessary for nonreciprocal devices (as will be discussed in Section 3 in Part 2). 3 Obviously, the permeability tensor has a singularity at ω = ω 0 , which is known as the ferromagnetic (or gyromagnetic) resonance. When the driving frequency ω is equal to the natural precession frequency ω 0 the energy from the microwave field is transferred most efficiently to the system of spins.…”

“…For direct measurements of the susceptibility tensor elements and to understand the operational principles of the Faraday rotators (see Section 2.1 in Part 2) 3 , it is convenient to represent the susceptibility in terms of the response to two circularly polarized microwave fields with opposite helicity. In this case, the effective susceptibility can be written as The positive helicity susceptibility χ + , which corresponds to the circularly polarized wave that rotates in the same direction as the precessional motion, has a singularity at ω = ω 0 .…”

“…Table 5). Co-U hexaferrites possess a very similar structure, (RSRSTS) 3 , to that of Co-Z hexaferrites. The density of ceramic hexaferrite was influenced considerably in that 4.2 g/cm 3 was achieved when prepared with high-energy milling, and 3.6 g/cm 3 when prepared with chemical co-precipitation.…”

“…E l e c t r o m e c h a n i c a l e f f e c t ( P i e z o e l e c t r i c i t y ) [ 3 ] E l e c t r o t h e r m a l e f f e c t ( P y r o e l e c t r i c i t y ) [ 1 ] Thermoelastic effect [2] P i e z o e l e c t r i c e f f e c t C o n v e r s e p i e z o e l e c tr i c e ff e c t Permittivity [2] E l e c t r o c a l o r i c e f f e c t P y r o e l e c t r i c e f f e c t …”

Synthesis and Structural Investigation of Nano-Sized Cadmium Ferrite

“…Soft magnetic ferrites are used as low frequency inductors, antenna rods and wide-band and for high frequency electronic devices such as electromagnetic wave absorbers or inductor devices, due to initial permittivity in high frequency. Ferrimagnets having low RF loss are used in passive microwave components such as isolators, circulators, phase shifters, and miniature antennas operating in a wide range of frequencies (1-100 GHz) and as magnetic recording media owing to their novel physical properties [1][2][3][4][5][6][7][8].Ferrite powder, one of the very important ferrite materials has been considered for many applications such as high density magnetic storage media, MRI contrast agent, colour imaging, ferro-fluids, high frequency devices, magnetic refrigerators, catalysts, humidity sensors, gas sensor, magnetic-fludies, photo-magnetic materials, site-specific drug delivery and microwave device [8][9][10].Due to the unparalleled physical and chemical properties, synthesis and applications of nano-particles are focused in the research. Materials are very attractive perspective of their scientific and technological importance.…”