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Electric and Magnetic Mode-Switchable Dual Antenna for Null Compensation
Kang, Hyunseong,Lim, Sungjoon IEEE 2013 IEEE antennas and wireless propagation letters Vol.12 No.-
<P>A novel dual antenna is proposed for null compensation. The primary antenna is a rectangular loop antenna that generates an electric-loop mode. A zeroth-order resonant (ZOR) antenna is used as the auxiliary antenna, which produces a magnetic-loop mode and reduces the overall antenna size. Since the auxiliary antenna can be placed inside the primary antenna, the overall occupied space is the same as the size of the single primary loop antenna. The electric- and magnetic-loop current distributions are orthogonal to each other, so their nulls are effectively compensated. The performances of the proposed antennas are demonstrated in both a full-wave simulation and experiments at 2.3 GHz.</P>
Kang, Hyunseong,Park, Seong-Ook IET 2016 IET microwaves, antennas & propagation Vol.10 No.14
<P>A novel substrate integrated waveguide (SIW) cavity backed slot antenna with low back radiation is proposed in this study. This newly proposed meta-mushroom antenna uses a SIW cavity to decrease the back radiation. It is fed by the SIW cavity backed slot and radiates by meta-mushroom structure. This antenna exhibits broadband characteristics due to the meta-mushroom structure and a bow-tie slot on the SIW. The back radiation of the proposed antenna is considerably diminished by the SIW cavity located at the back side maintaining high gain performance. After all, its front-to-back ratio is increased and maintained over 19.2 dB in the operating frequency band, 4.5-5.6 GHz. Full-wave simulation and experiments results of the proposed antenna are demonstrated.</P>
Hyunseong Kang,Sungjoon Lim Institute of Electrical and Electronics Engineers 2014 IEEE Transactions on Antennas and Propagation Vol. No.
<P>In this paper, we propose a novel electrically small dual-band reconfigurable antenna. By using a compact eighth-mode substrate integrated waveguide (EMSIW) structure, we designed a compact antenna. This antenna is capable of dual-band operation by additionally loading an electrically small complementary split-ring resonator (CSRR) structure. The EMSIW and CSRR structures are designed for satisfactory operations at bandwidths of 1.575 GHz [global positioning system (GPS)] and 2.4 GHz [wireless local area network (WLAN)], respectively. We load the CSRR with a varactor diode to achieve a narrow bandwidth and to enable the resonant frequency to continuously vary from 2.4 GHz to 2.5 GHz. Thus, we realize a channel selection function, which is used according to WLAN standards. Irrespective of the variation in the varactor diode voltage, the resonant frequency of the EMSIW is not varied, such that the antenna maintains a constant frequency at the GPS bandwidth even at different voltages. Consequently, as the DC bias voltage varies from 11.4 V to 30 V, the resonant frequency at the WLAN bandwidth continuously varies between 2.38 GHz and 2.5 GHz. We observe that the simulated and measured s-parameter values and radiation patterns are in good agreement with each other.</P>
상보적 분할 링 공진기를 이용한 전기적으로 작은 1/8 모드 기판 집적형 도파관 안테나
강현성(Hyunseong Kang),Somarith Sam,임성준(Sungjoon Lim) 한국전자파학회 2013 한국전자파학회논문지 Vol.24 No.7
본 논문은 기판 집적형 도파관(SIW: Substrate Integrated Waveguide)와 상보적 분할링 공진기(CSRR: Complementary Split Ring Resonator)를 기반으로 한 전기적으로 작은 안테나를 제안한다. 안테나의 전기적 크기는 CSRR과 기존 SIW의 1/8크기인 Eighth-Mode Substrate Integrated Waveguide(EMSIW)를 적용하여 줄일 수 있었다. EMSIW는 기존의 SIW와 비교하였을 때 공진 주파수는 유지하면서 단지 12.5 %의 크기를 차지한다. 또한, EMSIW 안에 CSRR을 회전함으로써 안테나의 방사 특성을 유지하면서 공진 주파수를 바꿀 수 있었다. CSRR을 0°부터 360°까지 회전시켜 공진 주파수를 4.74 GHz에서 5.07 GHz까지 변화를 줄 수 있었다. 단향성 방사 패턴이 발생하며, 그 최대 이득은 4.5 dBi에서 5.92 dBi로 관측되었다. Based on a substrate integrated waveguide(SIW) and a complementary split ring resonator(CSRR), electrically small antennas are proposed in this paper. Antenna"s electrical size is reduced by introducing both CSRR and the eighth-mode substrate integrated waveguide(EMSIW). The EMSIW occupies only 12.5 % of the conventional SIW at the same dominant resonant frequency. In addition, the resonant frequency of the antenna is varied by rotating the CSRR on the EMSIW while keeping the same radiation patterns. The resonant frequency is changed from 4.74 GHz to 5.07 GHz by varying orientation of the CSRR from 0 to 360 degree. Unidirectional radiation patterns are observed and the measured peak gains are from 4.50 to 5.92 dBi.
이중 대역 주파수 가변 1/8차 소형 기판집적형 도파관 안테나
강현성(Hyunseong Kang),임성준(Sungjoon Lim) 한국전자파학회 2014 한국전자파학회논문지 Vol.25 No.1
새로운 주파수 가변 이중 대역 안테나를 제안한다. 기존의 기판집적형 도파관(SIW: Substrate-Integrated Waveguide)에 비하여 1/8 크기를 갖는, 전기적으로 작은 1/8차 기판집적형 도파관(EMSIW: Eighth-Mode Substrate-Integrated Waveguide) 공진기 구조를 이용하여 전기적으로 작은 크기의 안테나를 설계하였다. 설계한 EMSIW 안테나 표면에 상보적 분할 링 공진기(CSRR: Complementary Split Ring Resonator) 구조를 추가적으로 탑재하여 이중 대역에서 동작할 수 있게 하였다. EMSIW와 CSRR 구조는 각각 1.575 ㎓(GPS), 2.4 ㎓ 대역(WLAN) 주파수 대역을 만족시킬 수 있어 이중 공진 특성을 만족하였다. 기본적으로 CSRR은 대역폭이 좁기 때문에 Varactor 다이오드를 탑재시켜 주파수를 2.4 ㎓에서 2.5 ㎓까지 연속적으로 가변할 수 있게 하였다. 그에 따라 WLAN 표준에서 사용하고 있는 채널 선택 기능 또한 구현할 수 있다. Varactor 다이오드에 따라 EMSIW의 공진은 독립적으로 고정되어 GPS 주파수 수신을 안정적으로 유지할 수 있도록 설계하였다. 결과적으로 DC 바이어스 전압을 11.4 V에서 30 V로 변경함에 따라 GPS 대역 주파수는 고정되어 있고, WLAN 대역의 공진 주파수가 2.38 ㎓에서 2.5 ㎓까지 연속적으로 변화한다. 시뮬레이션, 측정값 사이에 반사 손실, 방사 패턴 특성이 잘 일치함을 관찰할 수 있었다. In this paper, we propose a new frequency reconfigurable dual-band antenna. By using an electronically compact eighth-mode substrate-integrated-waveguide(EMSIW) resonator, we have designed a compact antenna, which performs dual-band movement by additionally loading a complementary split ring resonator(CSRR) structure. The EMSIW and CSRR structures are designed to satisfy the bandwidths of 1.575 ㎓(GPS) and 2.4 ㎓(WLAN), respectively. We load the CSRR with a varactor diode to allow a narrow bandwidth and to enable the resonance frequency to continuously vary from 2.4 ㎓ to 2.5 ㎓. Thus, we realize a channel selection function that is used in the WLAN standards. Irrespective of how a varactor diode moves, the EMSIW independently resonates so that the antenna maintains a fixed frequency of the GPS bandwidth even at different voltages. Consequently, as the DC bias voltage changes from 11.4 V to 30 V, the resonance frequency of the WLAN bandwidth continuously changes between 2.38 ㎓ and 2.5 ㎓, when the DC bias voltage changes from 11.4 V to 30 V. We observe that the simulated and the measured S-parameter values and radiation patterns are in good agreement with each other.
Somarith, Sam,Hyunseong Kang,Sungjoon Lim Institute of Electrical and Electronics Engineers 2014 IEEE Transactions on Antennas and Propagation Vol. No.
<P>A novel frequency reconfigurable substrate integrated waveguide-interdigital capacitor (SIW-IDC) antenna is presented. The antenna is designed based on a composite right/left-handed (CRLH) resonator, which is realized by the SIW-IDC. Thanks to CRLH characteristics, the antenna size is reduced. Since the IDC determines the resonant frequency, a varactor diode is embedded on the interdigital slot of the short-ended SIW. Its zeroth-order resonance (ZOR) frequency is varied from 4.13 GHz to 4.50 GHz by changing the bias voltage from 0 V to 36 V while keeping good impedance matching better than 15 dB. The radiation performance is numerically and experimentally investigated. Very good agreements between the simulated and measured S-parameters and radiation patterns are observed.</P>
Sungwook Choi,Hyunchul Yang,Hyunseong Kang,Gyeong Min Kim 대한견주관절학회 2019 대한견주관절학회지 Vol.22 No.4
Background: Clinical outcomes and prognosis of large and massive rotator cuff tears are known to be unpredictable not only in degeneration of the rotator cuff, but also due to a high rate of retear. Methods: Totally, 81 patients who had undergone arthroscopic rotator cuff repair from May 2008 to February 2016 were evaluated in our study. Clinical and functional evaluations were performed with the Constant score and the University of California, Los Angeles (UCLA) score, as well as full physical examination of the shoulder. All patients were confirmed to have magnetic resonance imaging (MRI) of tendon healing at least 1 year postoperatively. Results: The average age at the time of surgery was 65 years (range, 47–78 years). The average duration of postoperative time in which a follow-up MRI was performed was 36.1 months (range, 12–110 months). Large tears were present in 48 cases (59.3%) and massive tears in 33 cases (40.7%). Overall, there were 33 retear cases (40.7%). All the average clinical outcome scores were significantly improved at the last follow-up (p<0.001), although repair integrity was not maintained. Compared to type A, types C, and D of the Collin’s classification showed significantly higher retear rates (p=0.036). Conclusions: Arthroscopic rotator cuff repair yields improved clinical outcomes and a relatively high degree of patient satisfaction, despite the repair integrity not being maintained. Involvement of the subscapularis muscle or infraspinatus muscle had no effect on the retear rate.