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Hsien-Wen Liu

Bio: Hsien-Wen Liu is an academic researcher from National Taiwan University of Science and Technology. The author has contributed to research in topics: Antenna (radio) & Coaxial antenna. The author has an hindex of 10, co-authored 21 publications receiving 540 citations.

Papers
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Journal ArticleDOI
TL;DR: A coplanar waveguide (CPW)-fed planar monopole antenna with triple-band operation for WiMAX and WLAN applications is presented in this article, which occupies a small size of 25(L) × 25(W) × 0.8(H) mm3.
Abstract: A coplanar waveguide (CPW)-fed planar monopole antenna with triple-band operation for WiMAX and WLAN applications is presented. The antenna, which occupies a small size of 25(L) × 25(W) × 0.8(H) mm3, is simply composed of a pentagonal radiating patch with two bent slots. By carefully selecting the positions and lengths of these slots, good dual stopband rejection characteristic of the antenna can be obtained so that three operating bands covering 2.14-2.85, 3.29-4.08, and 5.02-6.09 GHz can be achieved. The measured results also demonstrate that the proposed antenna has good omnidirectional radiation patterns with appreciable gain across the operating bands and is thus suitable to be integrated within the portable devices for WiMAX/WLAN applications.

214 citations

Journal ArticleDOI
TL;DR: In this paper, a planar monopole antenna with standard band-notched characteristic suitable for ultrawideband (UWB) applications is presented, consisting of a square slot patch with a vertical coupling strip, only occupying a small size of 15 (L) × 15 (W) × 1.6 (H) mm3.
Abstract: A compact planar monopole antenna with standard band-notched characteristic suitable for ultrawideband (UWB) applications is presented. This microstrip-fed antenna, consisting of a square slot patch with a vertical coupling strip, only occupies a small size of 15 (L) × 15 (W) × 1.6 (H) mm3. By properly designing the strip placed at the center of the patch, good frequency rejection performance of the antenna with a wide operating band from 3.05 to 11.15 GHz can be obtained. Compared to other designs, the antenna has a quite simple structure to make the band-notched property to reduce the effect caused by the frequency interference. Furthermore, fairly good omnidirectional radiation patterns and transmission responses both indicate that the proposed antenna is well suited to be integrated within various portable devices for UWB operation.

141 citations

Journal ArticleDOI
TL;DR: In this paper, a compact inverted-F antenna with dual-band property for WLAN applications is presented, which can radiate with two operating bands covering 2.38-2.54 GHz and 4.99-5.96 GHz.
Abstract: In this letter, a novel compact inverted-F antenna with dual-band property for WLAN applications is presented. It comes with a C-shaped radiator and two meander shorting strips, which only occupy a small size of 35 (L)3 (W) mm to be easily embedded inside a laptop computer as an internal antenna. This design can radiate with two operating bands covering 2.38-2.54 and 4.99-5.96 GHz. By properly forming these two shorting strips, the effects due to the antenna near the external casing can be suitably tackled for actual application. Nearly omnidirectional coverage to enhance the communication quality can be obtained with our design. Therefore, the proposed antenna with a compact size is well suitable for WLAN operation in a laptop computer.

38 citations

Journal ArticleDOI
TL;DR: In this article, a folded dual-loop antenna suitable for GSM/DCS/PCS/UMTS applications is proposed, which is fabricated using a pair of symmetric meander strips to form two loops.
Abstract: A folded dual-loop antenna suitable for GSM/DCS/ PCS/UMTS applications is proposed. It is fabricated using a pair of symmetric meander strips to form two loops. By properly bending the radiating strips, the antenna can achieve a compact size of 50 (L) × 9 (W) × 9 (H) mm3 to be integrated within a mobile handset device as an internal antenna. With 6 dB return loss, two operating frequency bands covering 847-971 and 1670-2230 MHz can be obtained with our design. Moreover, the resonant characteristics of the antenna can be tuned by using various strip lengths and also spaces between the radiator and the ground plane. Experimental results exhibit that the proposed folded dual-loop antenna features nearly good omnidirectional radiation patterns with proper gain, so it is well suitable to meet GSM/DCS/PCS/UMTS operations for mobile handset applications.

34 citations

Journal ArticleDOI
TL;DR: In this article, a planar 2 × 2 microstrip array antenna with dual circular polarisation (CP) is presented, which can be reconfigured and operated with either the RH or LH CP by controlling the input state of the branch-line coupler.
Abstract: A planar 2 × 2 microstrip array antenna with dual circular polarisation (CP) is presented. This array can be reconfigured and operated with either the right-handed (RH) or left-handed (LH) CP by controlling the input state of the branch-line coupler. A prototype has been fabricated with a 0.4 mm-thick FR4 top layer for radiating elements and a 0.8 mm-thick FR4 bottom layer for a feeding network, where a 5 mm air spacing is inserted between them. Wide operating frequency ranges for RHCP and LHCP states can be achieved at about 1.55 GHz and 1.54 GHz, respectively. Good radiation properties across the operating band are also obtained so that the proposed array antenna is suitable for WLAN and WiMAX applications.

28 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, a miniaturized multifrequency antenna is proposed, which consists of a circular ring, a Y-shape-like strip, and a defected ground plane.
Abstract: A miniaturized multifrequency antenna is proposed. The proposed antenna can generate three separate impedance bandwidths to cover all the 2.4/5.2/5.8-GHz WLAN operating bands and the 2.5/3.5/5.5-GHz WiMAX bands. The proposed microstrip-fed antenna mainly consists of a circular ring, a Y-shape-like strip, and a defected ground plane. By adding a Y-shape-like strip in the circular ring, the antenna excites two resonant modes and is with miniaturization structure. Because of the introduction of the cambered ground plane with an isosceles triangle-defect, the third wide band with better impedance matching is obtained. A prototype is experimentally tested, and the measured results show good radiation patterns and enough gains across the operation bands.

251 citations

Journal ArticleDOI
TL;DR: In this paper, the design of a compact split ring resonator (SRR) loaded coplanar waveguide (CPW) fed ultrawideband circular monopole antenna having frequency notch characteristics is presented.
Abstract: This paper presents the design of a compact split ring resonator (SRR) loaded coplanar waveguide (CPW) fed ultrawideband circular monopole antenna having frequency notch characteristics. The electromagnetic coupling of the SRR with the CPW yields the frequency notch. Fabricated prototypes were measured and compared with simulations and good agreement was obtained. The impedance and radiation plots confirm the suppression of the desired notch frequency. A theoretical formulation to calculate the notch frequency is also proposed and validated.

192 citations

Journal ArticleDOI
TL;DR: In this article, a very compact coplanar waveguide-fed ultrawideband (UWB) printed monopole antenna with triple band-notched characteristics is presented, which uses three open-ended quarter-wavelength slots to create triple band notched characteristics in 3.3-3.7 GHz for WiMAX, 5.15-5.825 GHz for WLAN, and 7.25-7.75 GHz for X-band satellite communication systems.
Abstract: A very compact coplanar waveguide (CPW)-fed ultrawideband (UWB) printed monopole antenna (PMA) with triple band-notched characteristics is presented. The antenna uses three open-ended quarter-wavelength slots to create triple band-notched characteristics in 3.3-3.7 GHz for WiMAX, 5.15-5.825 GHz for WLAN, and 7.25-7.75 GHz for downlink of X-band satellite communication systems, respectively. The open-ended quarter-wavelength slot is analyzed in detail. Surface current distributions are used to show the effect of these slots. The antenna shows broad bandwidth and good omnidirectional radiation patterns in the passband, with a very compact size of 19 × 24 mm2.

178 citations

Journal ArticleDOI
TL;DR: In this article, a simple direct-fed dual-loop antenna capable of providing hepta-band WWAN/LTE operation under surroundings of an unbroken metal rim in smartphone applications is proposed.
Abstract: A simple direct-fed dual-loop antenna capable of providing hepta-band WWAN/LTE operation under surroundings of an unbroken metal rim in smartphone applications is proposed. The greatest highlight of this proposed antenna is that it provides a simple and effective multiband antenna solution for an unbroken metal-rimmed smartphone. The unbroken metal rim with 5 mm in height embraces the system circuit board of 130 $\, \times \,$ 70 mm $^{2}$ . Two no-ground portions of 10 $\, \times \,$ 70 mm $^{2}$ and 5 $\, \times \,$ 70 mm $^{2}$ are set on the top and bottom edge of the system circuit board, respectively. In-between the two separate no-ground portions, there is a system ground of 115 $\, \times \,$ 70 mm $^{2}$ connected with the unbroken metal rim via a small grounded patch which divides the unbroken metal rim into two strips. Finally, a dual-loop antenna is formed by combining the inner system ground and two strips. This proposed dual-loop antenna is capable of covering GSM850/900/DCS/PCS/UMTS2100/LTE 2300/2500 operating bands. Detailed design considerations of the proposed antenna are described and both experimental and simulation results are also presented and discussed.

146 citations

Journal ArticleDOI
TL;DR: In this article, a folded loop-inverted F reconfigurable antenna for mobile phone applications is designed and the obtained results are discussed in this communication, which operates in hepta-band, including GSM850, GSM900, GPS, DCS, PCS, UMTS and WLAN, with the return loss lower than 6 dB.
Abstract: A folded loop-inverted F reconfigurable antenna for mobile phone applications is designed and the obtained results are discussed in this communication. It is shown that loop antenna mode and an inverted F antenna (IFA) mode are controlled by only one p-i-n diodes with simple bias circuit. The impedance can be matched by adopting a matching bridge for both the loop and IFA modes. In a compact volume of 60 × 5 × 5 mm3, the proposed antenna operates in hepta-band, including GSM850, GSM900, GPS, DCS, PCS, UMTS and WLAN, with the return loss lower than 6 dB. A prototype of the proposed antenna is fabricated, measured, and obtained results including return loss, efficiency and gain, are presented.

144 citations