Browsing by Author "Liu, Nai-Chen"

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A Compact Planar Dual-Band Filtering Antenna
(2017-01-01)
Yen, Jui-Hsien
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Liu, Nai-Chen
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Chen, Keng-Hsien
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Tarng, Jenn-Hwan
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電信工程研究所
A compact planar dual-band filtering antenna is proposed. The design concepts in this paper achieve compacted size and reduce restrictions in the dual-band filtering antenna design. The filtering antenna utilizes an inverted U-shaped coupled line and a T-shaped feeding structure to compact the size without performance deterioration. A two-stage stepped-impedance resonator (SIR) is exploited for dual-band filtering. The SIR is bent into U-shape, and part of the inner ground is rectangularly slotted for Y-shaped antenna. The simulated and measured results show that proposed filtering antenna achieves operating frequency bands in 2.37 to 2.55 GHz and 4.93 to 5.73 GHz with peak radiation gain of 2 and 3.3 dBi, respectively. The proposed structure facilitates the dual-band filtering antenna design.
A Compact Size Four-Leaf Clover Shaped Antenna for On-Body Communications
(2016)
Chen, Keng-Hsien
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Liu, Nai-Chen
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Tarng, Jenn-Hwan
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電信工程研究所
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Institute of Communications Engineering
A compact size four-leaf clover shaped antenna for on-body communication is proposed. The proposed antenna consists of four antenna elements which are based on antipodal Vivaldi antennas (AVA). The combination of the four antenna elements is made for omnidirectional radiation in parallel to the surface of the human body. To achieve a compact combination of four AVA elements, the conducting planes around the tapered slot of AVA elements are bent. The contours of the tapered slot are optimized for wideband impedance matching. An overlap between AVA elements is created to obtain capacitive load and to reduce resonant length. The influence of the proximity of the human body on the proposed antenna is inapparent. The proposed antenna is built on the FR4 substrate with the size of 46 x 46 x 0.6 mm(3) and the bandwidth of 6 to 10.6 GHz, which is suitable for on-body communication applications.
A Small Satellite C-band SAR Mission Payload Definition for Disasters Management
(2013)
Yaung, James Yu-Chen
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Chen, Kun-Shan
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Chung, Shyh-Jong
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Yu, Shiann-Jeng
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Hung, Hao-Lun
Taiwan is an island with various high mountains created by tectonic plate collision where continent building is still active with numerous earthquake activities. Taiwan is also in one of the most prevalent monsoon and typhoon areas and they can bring along heavy precipitation that produce great threat of mud slide and land slide in the mountains. Remote mountain areas can only rely on satellite monitoring before, during, and after heavy rains where the optical monitoring satellites won\'t be able to provide the timely data or information. SAR satellites, with their advantages of all-weather capability, repeat pass, fine spatial resolution and wide swath, can provide coverage at disaster locations in the island, disaster assessment and resource survey provided the operating frequency to be lower enough as indicated in the low cost C-band SAR satellite payload defined in this paper. Based on the payload technology tradeoff analysis, the C-band system with GaN SSPA power amplifier was selected by comparing it with the X-band system with the TWTA technology which was described in our early stage of mission definition and analysis.
An Ultra-Wideband Millimeter Wave Aperture-coupled Patch Antenna Using a Comb-shaped Metasurface
(2019-01-01)
Hsu, Ching-Cheng
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Liu, Nai-Chen
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Wu, Sung-Jung
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Tarng, Jenn-Hwan
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交大名義發表
In this study, a novel ultra-wideband aperture-coupled patch antenna using a comb-shaped metasurface (MS) was investigated for millimeter wave applications. The proposed antenna was fabricated with 4 layers of PCB and can be realized based on two parts, an aperture coupling feeding network, and a radiator. The coupling feeding network comprises a microstrip line with a radial stub and a coupling aperture (slot line). The radiator is a combination of a driven patch and a comb-shaped MS, which are made of uniform 4 x 4 metallic patch cells. The driven patch is used to provide good coupling performance that conveys the current to be distributed on the comb-shaped MS. The comb-shaped MS also functions as a wideband radiator that enhances the impedance bandwidth. To validate the design, a prototype operating on 28 GHz to 56 GHz was fabricated and measured. The simulated and measured results are in reasonable agreement. The prototype antenna with dimensions of 0.45 lambda(0) x lambda(0) x 0.45 lambda(0) x 0.16 lambda(0), has a 10 dB impedance bandwidth of 65%, and a gain range of 5-8 dBi.
Compact Millimeter-wave Triband Quasi-Yagi Antenna for 5G and WiGig Applications
(2019-01-01)
Chen, Meng-Jie
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Liu, Nai-Chen
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Xue, Wei-Ren
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Tarng, Jenn-Hwan
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交大名義發表
Millimeter wave (mmWave) communication systems have become a potential candidate to deliver ultrahigh data throughput, e.g., 10 Gb/s owing to congestion in low frequency bands and requirements of high data throughput. According to FCC rules, 28, 37, 39 and 64-71 GHz bands have been suggested for next-generation wireless communication; in addition, Wireless Gigabit (WiGig) alliance also operates at an unlicensed 60 GHz band. Therefore, according to these proposed or developed wireless communication standards, we need multiband mmWave antennas. In this study, an antenna with a quasi-Yagi structure that consists of three arms and six spiral directors is proposed. To miniaturize the antenna, each arm plays multiple roles simultaneously, which include a driver, a reflector, a director, and/or an impedance matching network. In addition, the spiral directors are able to improve the antenna gain and enhance the impedance matching bandwidth at 60 GHz, simultaneously. The proposed antenna is compact (5 x 8 x 0.203 mm(3)) and the measurement results show that the antenna covers major 5G millimeter-wave bands (26.5-29.5 and 37-40 GHz) and the WiGig band (57-67 GHz). The measured peak gains of the proposed antenna are 6.2, 7.56 and 9.42 dBi, which correspond to 28, 38 and 60 GHz, respectively. The measured results confirm the good performances observed by electromagnetic simulations. The proposed mmWave triband antenna is suitable for mobile devices satisfying mmWave 5G and WiGig applications.