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C.H. Chao

Bio: C.H. Chao is an academic researcher from Feng Chia University. The author has contributed to research in topics: Slot antenna & WiMAX. The author has an hindex of 1, co-authored 1 publications receiving 30 citations.

Papers
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Journal ArticleDOI
TL;DR: This study presents a compact (32×32 mm2) coplanar waveguide-fed slot antenna design with dual-band operation for WLAN and WiMAX applications and achieves wide 10 dB bandwidth for the lower operating band.
Abstract: Owing to the recent demand to incorporate the two communication services, the wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX), therefore dual-band antennas that are designed with sufficient bandwidths to cover both WLAN and WiMAX operating bands are presently very important topics of research. Owing to the difficulty of simultaneously achieving both compactness and wideband, the dimensions of most dual-band slot antenna designs that are reported in recent literature exceed 35×40 mm2. Therefore this study presents a compact (32×32 mm2) coplanar waveguide (CPW)-fed slot antenna design with dual-band operation for WLAN (2.4/5.2/5.8 GHz) and WiMAX (2.3/2.5/3.5/5.7 GHz) applications. To achieve wide 10 dB bandwidth for the lower operating band (58%), the technique of applying a square-ring slot antenna type with an asymmetric ground plane was used herein, and a broad upper operating band (32%) was attained by introducing a stub-protruded monopole and loading a double-bent stub into one of the asymmetric CPW ground planes. The process of designing the proposed antenna is explicitly shown, and parametric studies were carried out by simulation. Typical experimental measurements were also conducted and compared with the simulated results.

33 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, a triple-band antenna for the frequency bands 2.4, 3.5 and 5 GHz is proposed for the IEEE 802.11a/b/g and 802.16e standards.
Abstract: This paper presents a compact triple band antenna for the frequency bands 2.4, 3.5 and 5 GHz. These bands are assigned to the IEEE 802.11a/b/g and IEEE 802.16e standards. The resonant modes for WLAN, WiMAX bands are achieved by employing a rectangular slot and a metamaterial inspired split ring structure. The extraction procedure of negative permeability for the proposed split ring resonator is discussed in detail. Tunability between the WLAN and WiMAX standards is demonstrated by using a single PIN diode. The proposed antenna with a compact size of 27 mm × 25 mm is fabricated and tested. The triple band antenna yields a −10 dB impedance bandwidth of about 18.6%, 4.3% and 40.3% in 2.4, 3.5 and 5 GHz bands respectively. Stable radiation patterns with low cross polarization and high average antenna gain of 2.46 dBi are observed for the operating bands.

82 citations

Journal ArticleDOI
TL;DR: In this paper, a compact metamaterial multiband antenna is proposed for wireless local area network (WLAN), worldwide interoperability for microwave access (WiMAX) and international telecommunication union (ITU) band applications using a modified Triangular Split Ring Resonator (TSRR).
Abstract: In this paper, a compact metamaterial multiband antenna is proposed for wireless local area network (WLAN), worldwide interoperability for microwave access (WiMAX) and international telecommunication union (ITU) band applications using a modified Triangular Split Ring Resonator (TSRR). In this work, we designed a modified TSRR with metamaterial property to obtain desirable negative permeability bands that help in accommodating all three frequency bands of interest in a single device. This approach leads to the considerable reduction of the device structure. The overall dimension of the proposed antenna structure has a compact size of 25.7 × 23.2 × 1.6 mm 3 and covers specific bands from the frequency spectra of 2.4/5.2/5.8, 3.5, and 8.2 GHz for WLAN, WiMAX, and ITU, respectively, with uniform radiation characteristics. The designed antenna structure is simulated using the High Frequency Structural Simulator (HFSS), and a prototype is developed and tested. The detailed analysis of the results obtained is presented. It is determined that the performance of the proposed antenna is superior to that of the existing antennas in the literature.

80 citations

Journal ArticleDOI
TL;DR: In this paper, a miniaturized ultra wideband (UWB) antenna with metamaterial for WLAN and WiMAX applications is designed Ghz using fractalization of the radiating edge and slotted ground structure approach.
Abstract: This paper presents a miniaturized ultra wideband (UWB) antenna with metamaterial for WLAN and WiMax applications. For miniaturization of UWB antenna resonating 3.1–10.6 is designed Ghz using fractalization of the radiating edge and slotted ground structure approach. A miniaturization of active patch area and antenna volume is achieved up to 63.48% and 42.24% respectively, with respect to the conventional monopole UWB antenna. This antenna achieves a 143% impedance bandwidth covering the frequency band from 2.54GHz to 15.36GHz under simulation and 132% (2.95–14.28 GHz) in measurement. The electrical dimension of this antenna is 0.32λ × 0.32λ (38mm×38mm) at lower frequency of 2.54GHz. As per IEEE 802.11a/b/g and IEEE 802.16e standards, WLAN (2.4–2.5 GHz, 5.150–5.250 GHz, 5.725–5.825 GHz), WiMAX (3.3–3.8 GHz) bands are achieved by using slotted ground structure and metamaterial rectangular split ring resonator. The proposed antenna is fabricated on FR4 substrate of thickness 1.6mm and a dielectric constant 4.3 and tested. The proposed antenna yields a −10 dB impedance bandwidth of about 11.1% (2.39–2.67 GHz), 59.1% (2.87–5.28 GHz) and 7.4% (5.58–6.01 GHz) under simulation and 4.5% (2.41–2.52 GHz), 51.1% (3.12–5.26 GHz) and 3.8% (5.69– 5.91GHz) in measurement for 2.4, 3.5 & 5 and 5.8GHz bands respectively. Stable radiation patterns with low cross polarization, high average antenna gain of 3.02 dBi under simulation and 2.14 dBi in measurement and measured peak average radiation efficiency of 76.6% are observed for the operating bands. Experimental results seem in good agreement with the simulated ones of the proposed antenna.

70 citations

Journal ArticleDOI
TL;DR: In this article, a planar monopole antenna with dual-band operation for WiFi and long-term evolution 4G (LTE) applications is presented, which is composed of a circular radiating patch with a smiling slot.
Abstract: A novel `coplanar waveguide'-fed planar monopole antenna with dual-band operation for WiFi and `long-term evolution 4G (LTE)' applications is presented. The simple antenna's geometry is composed of a circular radiating patch with a smiling slot, and it occupies a small size of 41.6( L ) × 28.38( W ) × 1.52( h ) mm 3 . Two operating bands covering 2.3-3.0 and 4.7-5.9 GHz are achieved by carefully optimising the position and size of a smiling slot. An antenna prototype has been manufactured and it has been characterised in terms of return loss and radiation pattern measurements in anechoic chamber exhibiting almost omnidirectional patterns and appreciable gain across the operating bands, being suitable for WiFi and 4G LTE applications.

27 citations

Journal ArticleDOI
TL;DR: In this paper, a concept of using slots both in the radiator and in the ground to miniaturize an ultrawideband (UWB) antenna in order to operate at multiband is demonstrated.
Abstract: A concept of using slots both in the radiator and in the ground to miniaturize an ultrawideband (UWB) antenna in order to operate at multiband is demonstrated. Initially, a miniaturized circular UWB antenna is designed which results in about 53.5% reduction in total volume and about 46.6% in the active patch area, in comparison to the conventional UWB antenna. To reconfigure the proposed UWB antenna to operate in multiband applications, slotted ground approach is used. The slots in the ground plane of the proposed design affects the surface current distribution due to which the designed antenna operates at 3.7 (middle WiMAX), 5.7 (upperWiMAX), and 7.5 GHz (X-band) with 210 dB reflection coefficient bandwidth of about 5.3% (3.64–3.84 GHz), 5.5% (5.64–5.96 GHz), and 3.7% (7.44– 7.72 GHz), respectively. The proposed configuration is compact in size with a total area of only 0.26k0 3 0.21k0530 3 24.85283.3 mm2; at lower resonating band of 2.6 GHz. The designed multiband structure yields good impedance matching, acceptable gain and stable radiation characteristics both in xz and yz plane, across their operational bandwidths.

24 citations