| 초록 |
In 5G and next-generation communications, high-frequency spectrum bands (millimeter wave) are required for ultra high speed massive data transfer. Silicate ceramics are of considerable promise as high frequency dielectrics in emerging millimetre wave applications. In the past, for microwave device applications, high dielectric constant (k) dielectric ceramics were desired for device miniaturization. However, for the millimetre wave region of the spectrum miniaturisation is not critical anymore and low values of k are sought because the low polarizability of such materials under a high frequency field reduces noise and inductive cross-talk and further allows for improved signal propagation velocity inside the material. Cordierite has a low K (εγ=5~6), and high Q, but has a narrow sintering range close to its melting point (1470 °C). Therefore, it is highly requested to reduce its sintering temperature by introducing proper sintering additives which do not harm the excellent Q of the cordierite. Amorphous cordierite nanoparticles were synthesized by hydrothermal method, and extensively studied their capability as a sintering additive to enhance sinterability of the crystalline cordierite. Densification behavior, crystallizations, microstructure, and dielectric properties at ultra high frequecies (15~24GHz) of the low-temperature processed cordierite ceramics are discussed. |
