Chih-Yu Huang

Realization of compact and broadband performances using the microstrip-line-fed slot antenna

The printed microstrip-line-fed broadband slot antenna is investigated in this paper. With the use of the offset microstrip feed line and the corner-truncated protruded ground plane, the bandwidth enhancement and the size reduction for the proposed slot antenna can be obtained. From experimental results, the measured impedance bandwidth, with a 10-dB return loss, can be up to 5210 MHz (108.2%) which is about 2.67 times of a conventional printed microstrip-line-fed rhombus slot antenna. Under the use of the protruded ground plane, antenna size can be reduced by about 52%. By selecting proper parameters of the proposed slot antenna, it can provide with the wireless communication services operating at WLAN/WiMAX bands.

S-shaped Monopole Antenna for Dual-band WLAN Applications

A coplanar waveguide (CPW)-fed S-shaped monopole antenna for 2.4/5 GHz dual-band operations is proposed. The proposed antenna can provide two separate impedance bandwidths of 209 MHz (about 8.5% centered at 2.45 GHz) and 1423 MHz (about 25.8% centered at 5.5 GHz), making it easily cover the required bandwidths for wireless local area network (WLAN) operations in the 2.4 GHz band (about 3.4% bandwidth required) and 5.2/5.8 GHz bands (about 12% bandwidth required). Details of the proposed antenna design and experimental results are presented and discussed.

Print a small size U-shape-modified broadband slot antenna on ceramic substrate

A microstrip-line-fed U-shaped modified slot antenna is designed and fabricated on AI2O3 ceramic substrate using the printing method. The influences of the length of microstrip-fed line and the thickness of AI2O3 ceramic on the characteristics of designed antennas are well defined in this study. As compared to other available current designs, the proposed structure of the fabricated antennas would offer the advantages of large bandwidth, large return loss, low profile and easy fabrication. Due to the larger dielectric constant of AI2O3 ceramic, the fabricated antenna has a small ground plane size of 30 mm x 30mm, and that is smaller than the slot antennas fabricated on a FR4 substrate. The fabricated slot antenna has a broad bandwidth of 275 MHz/8.9%, a high return loss of -28.0 dB and a maximum gain of 2.77 dBi at 3.12 GHz.

Slot antennas for UWB applications

A compact design of a slot antenna for application in UWB has been proposed. Investigations on adjusting cutting pie depths, flare angles, and stub slot length were performed. The proposed antenna provides UWB characteristics in a slot structure with simple impedance match technique.

Diverse resistive switching behaviors of AlN thin films with different orientations

Aluminum nitride (AlN) thin films with different orientations (i.e., amorphous, (100)- and (002)-oriented) are deposited on Pt/Ti/SiO2/Si substrates via the radio-frequency (RF) sputtering method. Among the three films, the amorphous AlN film is found to provide both the lowest leakage current (2.6 × 10−11 A) and the largest memory window size (3.1 × 106). Moreover, the observation results suggest that the thermal activation energy has a greater effect on the conduction behavior of the Ag/AlN/Pt structures than the microstructure, surface morphology, or chemical bonds.

Quasi-self-complementary antenna for multifunctional wireless applications

In this paper, a quasi-self-complementary antenna (QSCA) for multifunctional (i.e., wideband and dual-band wireless local area network (WLAN)) applications is presented. The proposed antenna consists of a pie-shaped radiating patch fed by a 50-Ω microstrip line and its complementary metal structure connected to the ground plane. With properly adjusting the angle (θ) of the pie-shaped notch and the pie-shaped stub on the ground plane, an alternative function of the antenna can be achieved. For θ = 0°, the antenna has a wide -10 dB impedance bandwidth of 4848 MHz (about 102% centered at 4.77 GHz). For θ = 25°, the wideband QSCA can be transformed to a progressive dual-band antenna and thus provides two separate impedance bandwidth of 292 MHz (about 11.9% centered at 2.45 GHz) and 1548 MHz (about 28.1% centered at 5.5 GHz). The measured results of the proposed antenna also exhibit respectable radiating patterns and gain values.

Printed quasi-self-complementary antenna for UWB applications

A quasi-self-complementary antenna (QSCA) for band-notched ultra-wideband (UWB) application free from interference with existing wireless local area network (WLAN) systems is proposed. The designed band-notched UWB operation can be obtained by choosing the size of the parasitic arc-shaped strip opposite to the quarter-circular patch. The proposed antenna has advantages of low cost, easy design and compact in size. Details of the proposed design and experimental results of the constructed antennas are presented.

Print parallel coupling wideband filters on Al 2 O 3 ceramic substrate

In this paper, low loss wideband 3 order parallel-coupled microstrip line filters are fabricated, and the influences of the designed parameters are well developed in this study. As the displacement parameter A increases, the insertion loss and ripple decrease and the bandwidth increases; As the displacement parameter B increases, the bandwidth decreases and the insertion loss and ripple increase. On the other word, for the purpose of low ripple and wideband, the best choice is to increase A and decrease B. For the interval parameters C and D, increasing of them will decrease bandwidth, for the reason of wideband, decrease the interval parameters (C and D) will be a good choice, however, the decrease of interval will also increase the coupling of each resonators. Due to the higher the dielectric constant and the high quality factor of the Al2O3 ceramic substrate, the wideband filters have the advantages of small size (about 25 mm x 6.2 mm), good insertion loss and the ripple characteristics in the passband, wide bandwidth and large left-transmission zero. From above results, the fabricated filters are suitable for the wideband microwave applications of WLAN system.