Chun-Yueh Huang

A HIGH BAND ISOLATION AND WIDE STOPBAND DIPLEXER USING DUAL-MODE STEPPED-IMPEDANCE RESONATORS

In this paper, a high performance diplexer is designed and fabricated for Global Positioning System (GPS) and wireless local area network (WLAN) applications simultaneously. The diplexer mainly comprises two dual-mode ring bandpass fllters (BPFs), operated at 1.575GHz and 2.4GHz, respectively. By using the stepped-impedance resonator (SIR) in the BPFs, the size reduction and wide stopband from 2.8GHz to 6GHz are obtained. Moreover, several transmission zeros are located at the passband edges, thus improving the passband selectivity. Due to impedance matching between two BPFs, a high

A Compact-Size and High Isolation Dual-Band Coplanar-Waveguide Bandpass Filter

A compact and high isolation CPW dual-band bandpass filter using the interdigital resonator structures (IDTRS) is presented for application in GPS and IEEE 802.11 b WLANs. Since the two passbands can be tuned individually, the filter has more design freedoms. IDTRS are used to generate and control the second passband frequency. Two transmission zeros in the stopband are realized to improve the selectivity of the filter, and to achieve a high isolation higher than 30 dB between two passbands. Good agreements between the simulated and measured results demonstrate our proposed structure.

Low Transparency Current Density and Low Internal Loss of 1060-nm InGaAs Laser With GaAsP–GaAs Superlattices as Strain-Compensated Layer

In this letter, the strained In_0.22Ga_0.78As-GaAs single quantum-well lasers grown by metal-organic vapor phase epitaxy were studied. The lasing wavelength of the fabricated InGaAs laser was 1056 nm, whereas the internal loss (alpha_i) and the transparency current density (J_tr) were 1.78 cm^-1 and 40.2 A/cm², respectively. By using the GaAsP-GaAs superlattices as strain-compensated layer, the lasing wavelength was 1052 nm, and the alpha_i and J_tr could be reduced to 0.63 cm^-1 and 39.1 A/cm², respectively. To the best of our knowledge, the J_tr was the lowest among the reported InGaAs lasers around 1060 nm.

An Inverse S-Shaped Slotted Ground Structure Applied to Miniature Wide Stopband Lowpass Filters

In this paper, an inverse S-shaped slotted ground structure (S-SGS) is proposed and analyzed. The S-SGS generates dual attenuation poles that can be easily controlled by its structure parameters. The equivalent circuit of the S-SGS consists of lumped elements that can be extracted from the measured S parameters. Moreover, several S-SGS cells are applied to form a miniaturized lowpass filter (LPF), which has a smaller area and a wider stopband in comparison to previous works.

Studies of InSb metal‐oxide‐semiconductor structure fabricated by photochemical vapor deposition using Si2H6 and N2O

Silicon oxide films (SiOx,0<x<2) have been prepared by photolysis of disilane (Si2H6) with nitrous oxide (N2O) at temperature below 200 °C using 2537‐A ultraviolet light. Ellipsometric studies prove that the refractive index and etching rate of the photo‐oxide films depend on the substrate temperatures and gas ratio. Composition and electrical properties of the interface (SiOx/InSb) are discussed by using Auger electron spectroscopy and metal‐oxide‐semiconductor capacitors. Hysteresis‐free capacitance‐voltage characteristics measured at 77 K are attained and the minimum interface state density is only 1.5×1011 cm−2 eV−1.

A Dual Mode BPF with Improved Spurious Response Using DGS Cells Embedded on the Ground Plane of CPW

A novel dual mode bandpass filter (BPF) with improved spurious response is presented in this letter. To obtain low insertion loss, the coupling structure using the dual mode resonator and the feeding scheme using coplanar-waveguide (CPW) are constructed on the two sides of a dielectric substrate. A defected ground structure (DGS) is designed on the ground plane of the CPW to achieve the goal of spurious suppression of the filter. The filter has been investigated numerically and experimentally. Measured results show a good agreement with the simulated analysis.