Yih-Chien Chen

Enhancement the Quality Factor of CaLa4Ti5O17 Microwave Ceramics Replacing La3+ with Nd3+ for Application in Rectenna

The microwave dielectric properties of CaLa(4-x)NdxTi5O17 ceramics were studied with a view to their potential for rectenna. The diffraction peaks of CaLa(4-x)NdxTi5O17 ceramics nearly unchanged as x increased from 0 to 0.007. The X-ray diffraction peaks of the CaLa3.995Nd0.005Ti5O17 ceramics revealed no significant variation of phase with sintering temperature. A dielectric constant of 57.2, a quality factor (Q × f) of 15700 GHz, and a temperature coefficient of resonant frequency (τf ) of −14 ppm/°C were obtained for CaLa3.995Nd0.005Ti5O17 ceramic sintered at 1500°C for 4 h.

Microwave Dielectric Properties of La(Mg0.5-xZnxSn0.5)O3 Ceramics

The microwave dielectric properties of La(Mg0.5-xZnxSn0.5)O3 ceramics were examined with a view to their exploitation for mobile communication. The La(Mg0.5-xZnxSn0.5)O3 ceramics were prepared by the conventional solid-state method with various sintering temperatures. The X-ray diffraction patterns of the La(Mg0.45Zn0.05Sn0.5)O3 ceramics revealed La(Mg0.45Zn0.05Sn0.5)O3 is the main crystalline phase, which is accompanied by small amounts of La2Sn2O7 as the second phases. Apparent density of 6.59 g/cm3, dielectric constant (ϵr ) of 19.82 and quality factor (Q × f) of 41,600 GHz were obtained for La(Mg0.49Zn0.01Sn0.5)O3 ceramics that were sintered at 1550°C for 4 h.

Phases and Microwave Dielectric Properties of CuO-Doped Nd(Mg0.5Sn0.5)O3 Ceramics

The influence of CuO on the microstructure and microwave dielectric properties of the Nd(Mg0.5Sn0.5)O3 ceramic were investigated with a view to their application in microwave devices. A CuO-doped Nd(Mg0.5Sn0.5)O3 ceramic system was prepared using the conventional solid-state method. The X-ray diffraction patterns of the CuO-doped Nd(Mg0.5Sn0.5)O3 ceramic did not significantly vary with sintering temperature. A dielectric constant of 19.5, a quality factor (Q × f) of 31,300 GHz, and a temperature coefficient of resonant frequency of −57 ppm/°C were obtained when the 0.5 wt% CuO-doped Nd(Mg0.5Sn0.5)O3 ceramic was sintered at 1400°C for 4 h.

Influence of B2O3 on Microstructure and Microwave Dielectric Properties of 0.45La0.97Sm0.03(Mg0.5Sn0.5) O3–0.55Ca0.8Sm0.4/3TiO3 Ceramic System

The influence of B2O3 on the microstructure and microwave dielectric properties of the 0.45La0.97Sm0.03(Mg0.5Sn0.5)O3–0.55Ca0.8Sm0.4/3TiO3 ceramic system were investigated with a view to their application in microwave devices. A B2O3-doped 0.45La0.97Sm0.03(Mg0.5Sn0.5)O3–0.55Ca0.8Sm0.4/3TiO3 ceramic system was prepared using the conventional solid-state method. The X-ray diffraction patterns of the B2O3-doped 0.45La0.97Sm0.03(Mg0.5Sn0.5)O3–0.55Ca0.8Sm0.4/3TiO3 ceramic system did not significantly vary with sintering temperature. A dielectric constant of 35.5, a quality factor (Q×f) of 5,500 GHz, and a temperature coefficient of resonant frequency of −1 ppm/°C were obtained when the 2 wt% B2O3-doped 0.45La0.97Sm0.03(Mg0.5Sn0.5)O3–0.55Ca0.8Sm0.4/3TiO3 ceramic system was sintered at 1450°C for 4 h.

Microwave Dielectric Properties of Mg1/3Nb2/3SnO4 Ceramics

The microwave dielectric properties of Mg1/3Nb2/3SnO4 ceramics were investigated for possible mobile communication applications. The Mg1/3Nb2/3SnO4 ceramics were prepared by conventional solid-state method with various sintering temperatures. The Mg1/3Nb2/3SnO4 ceramics contained MgNb2O6 and MgNb2SnO8. The intensity of the Mg1/3Nb2/3SnO4 ceramics increased with sintering temperature to a maximum at 1475°C. An apparent density of 5.95 g/cm3, a dielectric constant (ϵ r ) of 8.32, a quality factor (Q × f) of 84,800 GHz, and a temperature coefficient of resonant frequency (τ f ) of -11.1 ppm/OC were obtained when Mg1/3Nb2/3SnO4 was sintered at 1450°C for 4h.

Comparison of Fluorinated HfO2 and Si3N4 Charge Trapping Layer for Nonvolatile Flash Memories

Characteristics of fluorinated metal/SiO2/HfO2/SiO2/Si (F-MOHOS) and fluorinated metal/SiO2/Si3N4/SiO2/Si (F-MONOS) flash memory using gate fluorine ion implantation (GFI) have been investigated. Since dielectric constant of HfO2 is larger than Si3N4, electric field across on tunneling oxide of F-MOHOS flash memory is larger than F-MONOS flash memory, which results in faster program/erase speed. Moreover, HfO2 exhibits larger effective trapping density than Si3N4, which also contributes to faster program/erase speed for the F-MOHOS flash memory. Besides, charge retention of the F-MOHOS flash memory is superior than the F-MONOS flash memory, primarily due to larger conduction band offset at the HfO2/SiO2 interface (ΔEC = 1.7–2.0 eV) than at the Si3N4/SiO2 interface (ΔEC = 1.1 eV). F-MOHOS flash memory also exhibits superior program/erase endurance than F-MONOS flash memory. Therefore, F-MOHOS flash memory using GFI process is proposed to be suitable for future nonvolatile flash memory applications. On the other hand, larger dielectric constant of HfO2 inevitably induces larger electric field across on blocking oxide of F-MOHOS flash memory, then enhances electron back-tunneling from the gate electrode during erase operation, which results in obvious erase-saturation.

Dual band hybrid CPW fed planar monopole/dielectric resonator antenna

A dual band hybrid DR antenna consists of a CPW fed planar monopole and a circular-disk shape high permittivity dielectric resonator has been presented in this paper. The −10 dB S11 bandwidth of the dual band hybrid antenna is 28 % and 11 % in the ISM band and UNNI band, respectively. The radiation in the ISM and UNNI band are due to the CPW fed planar monopole and circular-disk shape dielectric resonator, respectively. The radiation patterns in the x−z and y−z plane in the ISM and UNNI band are symmetrical about the broadside. The peak gains are about 5.17 dBi and 7.88 dBi in the ISM band and UNNI band, respectively.

Dielectric Resonator Antenna Using 0.95MgTiO 3 - 0.05CaTiO 3 High Permittivity Ceramics

0.95MgTiO₃-0.05CaTiO₃ high-permittivity ceramic have been applied in the fabrication of dielectric resonator antenna. The permittivity and quality factor of 0.95MgTiO₃-0.05CaTiO₃ have been characterized. The dielectric resonator antenna is fed with a mico-strip line. Fabricated dielectric resonator antenna was measured by an Agilent N5230A network analyzer. The measurement result of the antenna composed of 0.95MgTiO₃-0.05CaTiO₃ dielectric resonator ( epsiv_r = 20.6, Qtimesf = 126 000) at 9.58 GHz has been presented. With this technique, a 5.92% bandwidth (return loss < 10 dB) of center frequency has been achieved.