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Fabrication and materials for magneto-photonic assemblies for high-gain antenna applications at GHz frequencies

Zhang, Lanlin
http://rave.ohiolink.edu/etdc/view?acc_num=osu1221248675

Abstract Details

2008, Doctor of Philosophy, Ohio State University, Materials Science and Engineering.
Recent magnetic photonic assembly (MPA) designs for high-gain antennas contain arrays of low-loss, anisotropic dielectrics and ferrimagnetic materials. Anisotropic dielectrics (AD) are fabricated from laminates, which consist of two ceramics with largely different permittivity and low dielectric losses at GHz frequencies. High gain has been demonstrated in a prototype antenna with 2 sets of 3 mutually rotated AD layers. These layers were made from laminates of commercially available α-Al2O3 and Nd-doped barium titanate. Equivalent permittivity tensors and loss tangents (tanδ~1.9x10-3) were characterized using a resonant cavity based approach, coupled with a finite-element method (FEM) full-wave solver. To enable further minimization of dielectric loss, dense high-purity α-Al2O3 and TiO2 were prepared starting from colloidally stabilizing the powders in aqueous HNO3 or NH3. After colloidal filtration and sintering, α-Al2O3 with >97.9% density was achieved at a sintering temperature of 1300°C, and TiO2 with >99.5% density was obtained at 1000°C. These low sintering temperatures are ascribed to excellent compact homogeneity. TiO2 was obtained with tanδ of 1.4x10-4 at 6.4GHz at room temperature. This relatively low value is attributed to the homogeneous dense microstructure with 2.2µm grain size. Al3+ was doped into TiO2 using a modified infiltration method to compensate for the effect of Ti4+ reduction. A homogeneous microstructure and doping concentration were also observed in the doped dense TiO2. Substituted Y3Fe5O12 (YIG) garnet was chosen as the ferrimagnetic (F) component, due to its pronounced Faraday rotation effect and potentially low magnetic and dielectric loss. Phase pure garnet was prepared by using the citric-gel method. The magnetic properties were studied for Ca,V,Zr-substituted YIG (CVZG) and as-prepared particle morphology. Compacts of CVZG submicron particles were found to possess a low loss at GHz frequencies, and will be applied in future MPAs structures.
Hendrik Verweij (Advisor)
Materials Science

Recommended Citations

Citations

  • Zhang, L. (2008). Fabrication and materials for magneto-photonic assemblies for high-gain antenna applications at GHz frequencies [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1221248675

    APA Style (7th edition)

  • Zhang, Lanlin. Fabrication and materials for magneto-photonic assemblies for high-gain antenna applications at GHz frequencies. 2008. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1221248675.

    MLA Style (8th edition)

  • Zhang, Lanlin. "Fabrication and materials for magneto-photonic assemblies for high-gain antenna applications at GHz frequencies." Doctoral dissertation, Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1221248675

    Chicago Manual of Style (17th edition)

osu1221248675
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© 2008, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.