| Millimeter-wave Dielectric Ceramics of Alumina and Forsterite with High Quality factor and Low Dielectric Constant |
| Hitoshi Ohasto, Tsutomu Tsunooka1, Minato Ando1, Yoshihiro Ohishi, Yasuharu Miyauchi2, Ken ichi Kakimoto |
Department of Materials Science and Technology, Nagoya Institute of Technology
1Japan Fine Ceramics Center,
2Materials Research Center |
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| ABSTRACT |
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Millimeter-wave dielectric ceramics have been used like applications for ultrahigh speed wireless LAN because it reduces the resources of electromagnetic wave, and Intelligent Transport System (ITS) because of straight propagation wave. For millimeterwave, the dielectric ceramics with high quality factor (Q$.$f), low dielectric constant($varepsilon$), and nearly zero temperature coefficient of resonant frequency ($tau$) are needed. No microwave dielectric ceramics with these three properties exist except Ba(Mg$_$1/3/Ta/sub1/3/)O$_3$ (BMT), which has a little high s: In this paper, alumina (Al$_2$O$_3$) and fosterite (Mg$_2$SiO$_4$), candidates for millimeter-wave applications, were studied with an objective to get high q$.$f and nearly zero $tau$$_$f/ For alumina ceramics, q$.$f more than 680,000 GHz was obtained but it was difficult to obtain nearly zero Qf. On the other hand, for forsterite ceramics, q$.$f was achieved from 10,000 GHz of commercial for sterite to 240,000 GHz of highly purified MgO and SiO$_2$ raw materials, and $tau$$_$f/ was reduced a few by adding TiO$_2$ with high positive $tau$$_$f/ |
| Key words:
Millimeter-wave dielectric materials, Microwave materials, Alumina, Fosterite, Quality factor |
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