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W-Band Reflectarray Antenna using Metal Grid Mesh Unit-Cells
Seongmin Pyo(표성민),Kichul Kim(김기철) 대한전기학회 2021 전기학회논문지 P Vol.70 No.2
In this paper, a novel horn-fed reflectarray antenna using a 2-state metal grid mesh unit-cells operating at W-band is proposed. The radiating elements are printed above a 1.57 mm-thick substrate with a dielectric constant of 2.2 and the reflectarray is fed by a 15 dBi pyramidal horn antenna placed 53 mm away from the aperture center. The proposed antenna operates at 80 GHz while using two metal mesh grid of sizes 0.9 mm and 1.1 mm for the phase compensation on the aperture surface. These two metal mesh grid patches form a total of 193 radiating unit cells on a 30 mm square aperture surface and are spaced 0.5 wavelength apart. The proposed reflectarray antenna achieves a gain of 22.23 dBi at the operating frequency while maintaining 4.9° of half-power beamwidth in both the E- and H-planes over a wide bandwidth from 70 GHz to 90 GHz.
Seongmin Pyo,Sang-Min Han,Jung-Woo Baik,Young-Sik Kim IEEE 2009 IEEE transactions on microwave theory and techniqu Vol.57 No.11
<P>In this paper, a new composite right/left-handed transmission line (CRLH-TL) with equilateral slots is proposed for efficiency-improved zeroth-order resonant antennas. A 1-D infinitesimal equivalent transmission line circuit model is derived, and the characteristic impedance and dispersive relation are theoretically computed. Based on the isotropic arranged unit cells of the slot-loaded composite right/left-handed transmission line (SL CRLH-TL), 2-D zeroth-order resonators are designed for planar magnetic monopole antenna applications. The SL CRLH-TL provides the zeroth-order resonance with some degradation of the quality factor. Therefore, a highly efficient radiating resonator can be designed with higher gain at the zeroth-order frequency. The theoretical approach was verified by the experimental results. The radiation efficiency was improved by up to 45.6% for the nine-rectangular zeroth-order resonant antenna and 21.4% for the seven-hexagonal zeroth-order resonant antenna without degrading the radiating performance. Moreover, the antenna gains of these two antennas were enhanced by 7.56 and 6.31 dB, respectively, due to the increase of the radiation efficiency.</P>
Frequency and circular‐polarization switchable microstrip antenna for dynamic spectrum allocation
Pyo, Seongmin,Jo, Han‐,Shin,Park, Sung‐,Ho,Park, Jong‐,Sung,Lee, Hyungjoo John Wiley Sons, Inc. 2018 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS Vol.60 No.11
<P><B>Abstract</B></P><P>This article presents a novel frequency‐reconfigurable microstrip antenna supported with an opposite circular polarization sense for dynamic spectrum allocation. The degenerate TM<SUB>10</SUB> and TM<SUB>01</SUB> frequencies are designed by using the distinctly separated electrical delay depending on the H‐shaped slot along the feeding positions for generating circularly polarized waves. In addition, the circularly polarization sense is controlled by changing the status of the pin diode because the switched vertical path affects only TM<SUB>10</SUB> frequency without changing horizontal TM<SUB>01</SUB> frequency. To verify the feasibility of the proposed antenna, the conceptual equivalent circuit is established and the experimental validation is carried out. The implemented antenna successfully demonstrates frequency‐reconfigurable capability with opposite circular polarizations and shows a good agreement with the simulation results.</P>
Characterization of interdigital stub with defected ground structure
Pyo, Seongmin,Baik, Jung-Woo,Lee, Dong-Hyo,Kim, Young-Sik Wiley Subscription Services, Inc., A Wiley Company 2009 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS Vol.51 No.5
<P>A new scheme with an interdigital line and a defected ground structure for dual-band operation is dealt with in this letter. The proposed structure is analyzed using a series L-C resonator model added a parasitic shunt capacitance. The nonlinear phase of this structure is dependent on the dumbbell size of the defected ground. This proposed scheme is applicable for a short-ended stub circuit and a dual pass-band filter at the centre frequencies of 860 and 1810 MHz. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1353–1356, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24331</P>
휴대용 UHF대역 RFID 시스템을 위한 선형 테이퍼드 슬롯 정류 안테나
표성민(Seongmin Pyo) 한국전기전자학회 2020 전기전자학회논문지 Vol.24 No.1
본 논문에서는 휴대용 UHF대역 RFID 시스템을 위한 선형 테이퍼드 슬롯 정류 안테나를 제안하였다. 제안한 정류 안테나는 별도의 유전체 기판을 사용하지 않기 때문에, 얇은 금속 두께로 평판형 안테나를 구현하였다. 정류 안테나는 입력 RF전력을 출력 DC전압으로 전환하는 정류회로는 2개의 쇼트기 다이오드를 이용한 배전압회로를 이용하였으며, 선형 테이퍼드 슬롯 안테나에 집적하여 정류 안테나를 설계하였다. 배전압 정류회로와 선형 테이퍼드 슬롯 안테나의 임피던스 공액정합을 위하여, 테이퍼드 슬롯의 각도와 안테나 급전선의 길이의 조절을 통해 source-pull 방법을 이용하였다. 제안한 안테나 시제품은 자유공간 무선환경실험 환경에서 RF-DC전환 실험과 원거리장 안테나 방사패턴 측정실험을 통해 회로 및 방사 특성을 검증하였다. 최종 제안한 안테나는 중심주파수 915 MHz 기준으로 0.23-파장(75 mm)와 0.18-파장(60 mm) 크기로 소형화하였다. In this paper, we propose a linear tapered slot rectifying antenna for a portable UHF-band RFID system. Since the proposed rectifying antenna does not use a dielectric substrate, the planar antenna is implemented with a thin metal thickness. The rectifier circuit converts input RF power into output DC voltage using a voltage doubler circuit based on two anti-parallel schottky diodes. The rectifying antenna is integrated by the voltage doubler circuit into a linear tapered slot antenna. For conjugate impedance matching of the rectifying circuit and the linear tapered slot antenna, the source-pull method was utilized by adjusting the angle of the tapered slot and the length of the antenna feed line. The proposed antenna prototype has been verified with the electrical and radiation characteristics through RF-DC conversion and far-field radiation test in open space measurement environment. Finally, the proposed antenna is realized to 0.23-wavelength (75 mm) and 0.18-wavelength (60 mm) at 915 MHz center frequency.
Compact Circularly Polarized Microstrip Antennas Using EM Coupled Loop Resonators
CHOI, Junho,PYO, Seongmin,HAN, Sang-Min,KIM, Young-Sik The Institute of Electronics, Information and Comm 2010 IEICE TRANSACTIONS ON COMMUNICATIONS - Vol.93 No.10
<P>In this letter, compact loop resonator type circular polarization (CP) antennas with a square ring and an X-shaped meander loop are presented. Both antennas are fed to a microstrip line with electromagnetic coupling. By adjusting the gap and length of a coupled microstrip line, the magnitude and phase conditions of two orthogonal modes for CP can be determined. The proposed antennas show good axial ratios and also good agreements between experimented and simulated results.</P>