Electrical and optical properties of CaCu3Ti4O12 (CCTO) substrates for
microwave devices and antennas
MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, 39 (2):
145-150 (2003)DOI: 10.1002/mop.11152
Zusammenfassung
The solid-state procedure is used to produce bulk ceramics of CCTO
(CaCu3Ti4O12). The samples of the CCTO ceramic are studied by X-ray
powder diffraction and infrared and Roman scattering spectroscopy. The
infrared and Raman scattering spectroscopy confirm the formation of the
CCTO phase, as seen by X-ray diffraction (XRD) analysis. One
experimental procedure uses an organic binder in the process of shaping
the samples. In the second procedure, the samples were prepared without
the presence of the organic phase, and we obtained a higher dielectric constant (K = 7370) with higher loss (D = 0.2) at 1 KHz. For the first procedure, a lower dielectric constant (K 1530) and lower loss (D =
0.11) at 1 KHz were obtained. Simple rectangular antenna prototypes were
also designed on substrate samples (C1, C2, P1, and P2). For the
antennas with P2, C1, and C2 as substrates, the bandwidth (BW) is 90 MHz
(around 3%). The antenna with P1 substrate presents a surprisingly high
BW of 270 MHz, which corresponds to a 10% bandwidth. Such a value is in
accordance with the requirements for planar antennas in a variety of
wireless communication systems such as WLAN, PCS, Wi-Fi, and other
protocols. Therefore, these measurements confirm the potential use of
such materials for small high-dielectric planar antennas (HDAs). These
materials are also attractive for capacitor applications as well as for
microelectronics and microwave devices (cellular mobile phones, for
example), where miniaturization of the devices is crucial. (C) 2003
Wiley Periodicals, Inc.