A Compact, Wideband, Two-Port Substrate-Integrated Waveguide Antenna With a Central, Double-Slotted, Metallic Plate Flanked by Two Paired of Corrugations for Radar Applications

Jin, Yunnan,Lee, Hojoo,Choi, Jaehoon Institute of Electrical and Electronics Engineers 2018 IEEE transactions on antennas and propagation Vol.66 No.11

<P>This communication proposes a compact, wideband, two-port substrate-integrated waveguide (SIW) antenna with a central, double-slotted metallic plate flanked by two paired corrugations for radar applications. The proposed antenna uses a two-layer structure, with a slotted metallic plate with corrugations on the top layer and an FR-4 substrate SIW on the bottom layer. The antenna has compact dimensions of 63 mm <TEX>$\times$</TEX> 54 mm ( <TEX>$2.32\lambda _{0} {\times}\,\, 1.99\lambda _{0}$</TEX>) with a low profile of 7 mm ( <TEX>$0.26\lambda _{0}$</TEX>). To understand the operating principle of the two-port SIW antenna clearly, modal analysis is performed for single-port SIW antenna. The antenna satisfies a −10 dB reflection coefficient from 10.15 to 11.58 GHz. Although the separation between the two central slots is minimized to 4 mm ( <TEX>$0.14\lambda _{0}$</TEX>), the isolation performance remains excellent (less than −30 dB). The gain enhancement, with a narrow beam pattern for radar applications, is realized using constructive superposition of in-phase electromagnetic energy from the two slots. In addition, because the antenna has two ports, it also has a beam scanning function from −12° to +12° in its boresight direction. The experimental and simulated results from the proposed antenna are in good agreement.</P>

A planar UWB MIMO antenna with gain enhancement and isolation improvement for the 5G Mobile platform

Jin, Yunnan,Ko, Minbeom,O, Yeonjeong,Choi, Jaehoon John Wiley Sons, Inc. 2019 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS - Vol.61 No.4

<P><B>Abstract</B></P><P>A planar ultra‐wide band (UWB) multi‐input multi‐output (MIMO) antenna with gain enhancement and isolation improvement for the 5G mobile platform is proposed. The proposed antenna consists of two planar UWB low‐band antenna elements: a compact multi‐loop antenna and a ground‐slotted planar inverted F antenna (PIFA) located on the opposite side of the rectangular ground plane. These two antennas satisfy the 10‐dB return loss bandwidth from 2.90 to 6.94 GHz for multi‐loop antenna and from 2.79 to 7.23 GHz for slotted PIFA antenna, respectively. A high isolation level of greater than 20 dB is realized without applying any additional decoupling structures. The realized gains are larger than 2.9 dBi. The experimental and simulated results of the proposed antenna are in good agreement with each other.</P>

Efficient Synthesis of Functionalized 1-oxo-1-phenyl-2-acetic Acids through Ru(II)-catalyzed Transfer Hydrogenation

Xiaowei Wang,Yunnan Yan,Binwei Gong,Xiaobo Tang,Qiu Li,Yanqiu Meng,H. Eric Xu,Wei Yi 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.10

A Study of Segmental and Syllabic Intervals of Canonical Babbling and Early Speech*

( Xiaoxiang Chen ),( Yunnan Xiao ) 경희대학교 비교문화연구소 2012 비교문화연구 Vol.28 No.-

Interval or duration of segments, syllables, words and phrases is an important acoustic feature which influences the naturalness of speech. A number of cross-sectional studies regarding acoustic characteristics of children`s speech development found that intervals of segments, syllables, words and phrases tend to change with the growing age. One hypothesis assumed that decreases in intervals would be greater when children were younger and smaller decreases in intervals when older (Thelen ,1991 ), it has been supported by quite a number of researches on the basis of cross-sectional studies (Tingley & Allen, 1975; Kent & Forner, 1980; Chermark & Schnerderman, 1986), but the other bypothesis predicted that decreases in intervals would be smaller when children were younger and greater decreases in intervals when older (Smith, Kenney & Hussain, 1996). Researchers seem to come up with conflicting postulations and inconsistent results about the change trends concerning intervals of segments, syllables, words and phrases, leaving it as an issue unresolved. Most acoustic investigations of children`s speech production have been conducted via cross-sectional designs, which involves studying several groups of children, So far, there are only a few longitudinal studies, This issue needs more longitudinao investigations; moreover, the acoustic measures of the intervals of child speech are hardly available. All former studies focus on word stages excluding the babbling stages especially the canonical babbling stage, but we need to find out when concrete changes of intervals begin to occur and what causes the changes. Therefore, we conducted an acoustic study of interval characteristics of segments and words concerning Canonical Babble (CB) and early speech in an infant aged from 0;9 to 2;4 acquiring Mandarin Chinese, The current research addresses the following two questions: 1, Whether decreases in interval would be greater when children were younger and smaller when they were older or vice versa? 2. Whether the child speech concerning the acoustic features of interval drifts in the direction of the language they are exposed to? The female infant whose L1 was Southern Mandarin living in Changsha was audio- and video-taped at her home for about one hour almost on a weekly basis during her age range from 0;9 to 2;4 under natural observation by us investigators. The recordings were digitized. Parts of the digitized material were labeled. All the repetitions were excluded. The utterances were extracted from 44sessions ranging from 30 minutes to one hour. The utterances were divided into segments as well as syllable-sized units. Age stages are 0;9-1;0,1;1-1;5, 1;6-2;0,2;1-2;4. The subject was a monolingual normal child from parents with a good education. The infant was audio-and video-taped in her home almost every week. The data were digitized, segments and syllables from 44sessions spanning the transition from babble to speech were transcrtbed in narrow IPA and coded for analysis. Babble was coded from age 0;9-1;0 , and words were coded from 1;0 to 2;4, the data has been checked by two professionally trained persons who majored in phonetics. The present investigation is a longitudinal analysis of some temporal characteristics of the child speech during the age periods of 0;9-1;0, 1;1-1;5, 1;6-2;0, 2;1-2;4. The answer to Research Question 1 is that our results are in agreement with neither of the hypotheses. One hypothesis assumed that decreases in intervals would be greater when children were younger and smaller decreases in intervals when older (Theln ,1991); but the other hypothesis predicted that decreases in intervals would be smaller when children were younger and greater decreases in intervals when older (Smith, Kenney & Hussain, 1996). On the whole, there is a tendency of decrease in segmental and syllabic duration with the growing age, but the changes are not drastic and abrupt. For example, /a/ after /k/ in Table 1 has greater decrease during 1;1-1;5, while /a/ after /p/, /t/ and /w/ has greater decrease during 2;1-2;4. /ka/ has greater decrease during 1;1-1;5, while /ta/ and /na/ has greater decrease during 2;1-2;4. Across the age periods, interval change experiences lots of fluctuation all the time. The answer to Research Question 2 is yes. Babbling stage is a period in which the children`s acoustic features of intervals of segments, syllables, words and phrases is shifted in the direction of the language to be learned, babbling and children`s speech emergence is greatly influenced by ambient language. The phonetic changes in terms of duration would go on until as late as 10-12 years of ambient language, the variation, the variation would be less and less until they attain the adult-like competence. Via the analysis of the SPSS 15.0, the decrease of segmental and syllabic intervals across the four age periods to be of no significant is continuous. It reveals that the process of child speech development is gradual and cumulative.

Compact Mobile Quad-Band Slot Antenna Design for GPS L1, WiMAX, and WLAN Applications

Haiyan Piao,Jaehoon Choi,Yunnan Jin,Jinpil Tak 한국전자파학회JEES 2017 Journal of Electromagnetic Engineering and Science Vol.17 No.2

In this paper, an asymmetric compact multiband slot antenna is proposed for global positioning system (GPS), worldwide interoperability for microwave access (WiMAX), and wireless area network (WLAN) applications. The top plane, a ground is composed of a rectangular slot with a trapezoidal-like stub, an inverted U-shaped slot at the right side of the rectangular slot, an inverted L-shaped slot at the left side of the rectangular slot, and three stubs. The proposed antenna is fed by an asymmetric cross-parasitic strip on the bottom plane. By properly designing the slots and stubs, four resonant frequency bands are achieved with -10 dB reflection coefficient bandwidths of 50 MHz, 400 MHz, 390 MHz, and 830 MHz in the 1.57 GHz GPS band, 2.4 GHz WLAN band, 3.5 GHz WiMAX band, and 5.5 GHz WLAN bands, respectively. The antenna has a total compact size of 13 mm × 32 mm × 0.8 mm. Simulated and measured results indicate that the proposed antenna has sufficient bandwidth and good radiation performance in each band.

Inkjet Catalyst Printing and Electroless Copper Deposition for Low-Cost Patterned Microwave Passive Devices on Paper

Benjamin S. Cook,Yunnan Fang,Sangkil Kim,Taoran Le,W. Brandon Goodwin,Kenneth H. Sandhage,Manos M. Tentzeris 대한금속·재료학회 2013 ELECTRONIC MATERIALS LETTERS Vol.9 No.5

A scalable, low-cost process for fabricating copper-based microwave components on flexible, paper-based substrates is demonstrated. An inkjet printer is used to deposit a catalyst-bearing solution (tailored for such printing) in a desired pattern on commercially-available, recyclable, non-toxic (Teslin®) paper. The catalystbearing paper is then immersed in an aqueous copper-bearing solution to allow for electroless deposition of a compact and conformal layer of copper in the inkjet-derived pattern. Meander monopole antennas comprised of such electroless-deposited copper patterns on paper exhibited comparable performance as for antennas synthesized via inkjet printing of a commercially-available silver nanoparticle ink. However, the solution-based patterning and electroless copper deposition process avoids nozzle-clogging problems and costs associated with noble metal particle-based inks. This process yields compact conductive copper layers without appreciable oxidation and without the need for an elevated temperature, post-deposition thermal treatment commonly required for noble metal particle-based ink processes. This low-cost copper patterning process is readily scalable on virtually any substrate and may be used to generate a variety of copper-based microwave devices on flexible, paper-based substrates.

Quadruple Band-Notched Trapezoid UWB Antenna with Reduced Gains in Notch Bands

Jaehoon Choi,Jinpil Tak,Yunnan Jin 한국전자파학회JEES 2016 Journal of Electromagnetic Engineering and Science Vol.16 No.1

A compact ultra-wide band antenna with a quadruple band-notched characteristic is proposed. The proposed antenna consists of a slotted trapezoid patch radiator, an inverted U-shaped band stop filter, a pair of C-shaped band stop filters, and a rectangular ground plane. To realize the quadruple notch-band characteristic, a U-shaped slot, a complementary split ring resonator, an inverted U-shaped band stop filter, and two C-shaped band stop filters are utilized in this antenna. The antenna satisfies the –10 dB reflection coefficient bandwidth requirement in the frequency band of 2.88–12.67 GHz, with a band-rejection characteristic in the WiMAX (3.43–3.85 GHz), WLAN (5.26–6.01 GHz), X-band satellite communication (7.05–7.68 GHz), and ITU 8 GHz (8.08–8.87 GHz) signal bands. In addition, the proposed antenna has a compact volume of 30 mm× 33.5 mm× 0.8 mm while maintaining omnidirectional patterns in the H-plane. The experimental and simulated results of the proposed antenna are shown to be in good agreement.

Efficient Synthesis of Functionalized 1-oxo-1-phenyl-2-acetic Acids through Ru(II)-catalyzed Transfer Hydrogenation

Wang, Xiaowei,Yan, Yunnan,Gong, Binwei,Tang, Xiaobo,Li, Qiu,Meng, Yanqiu,Xu, H. Eric,Yi, Wei Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.10

Nitrogen Fixation by Ru Single-Atom Electrocatalytic Reduction

Tao, Hengcong,Choi, Changhyeok,Ding, Liang-Xin,Jiang, Zheng,Han, Zishan,Jia, Mingwen,Fan, Qun,Gao, Yunnan,Wang, Haihui,Robertson, Alex W.,Hong, Song,Jung, Yousung,Liu, Shizhen,Sun, Zhenyu Elsevier 2019 Chem Vol.5 No.1