• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.21 no.2
• /
• pp.143-151
• /
• 2010

In this paper, a novel rectangular patch antenna is proposed to have Zeroth Order Resonance(ZOR) generated based on the Metamaterial Complosite Right- and Left-Handed(CRLH) structure. Making the in-phase electric field over the entire antenna other than a half-wavelength as the fundamental resonance mode of a standard microstrip patch or its positive multiple, the metallic patch is suggested to be capacitively coupled with only one surrounding rectangular ring, different from the previous 1D ZOR antennas commonly having several metal cells in line. The performance of the proposed antenna is simulated by a 3D field solver that inputs the sizes of the physical structure corresponding to the equivalent circuit designed to have ZOR at 2.4 GHz. Consequently, the resonance frequency, the gain and the antenna efficiency are observed 2.4 GHz, 5 dB and 98%, respectively. Besides, the important property of the proposed antenna is addressed as the combination of the low profile as an advantage of microstrip patch antennas, and the omni-directional field pattern typical of monopole antennas.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.19 no.2
• /
• pp.223-230
• /
• 2008

A CRLH-TL based compact metamaterial antenna on a magneto-dielectric material is proposed. The proposed antenna is composed of two patches and vias, which is loaded by a magneto-dielectric material constructed by SRRs. The characteristic of SRRs is studied, and the size reduction of the antenna by using the magneto-dielectric material is confirmed. The simulated resonant frequency of the antenna has showed a decrease of 7.13 % at - 1st-order resonant mode, and 23.9 % at zeroth-order resonant mode. A zeroth-order resonant antenna is fabricated and measured, which has a resonant frequency of 1.888 GHz, a bandwidth of 0.48 %, a gain of 0.534 dBi, and an efficiency of 51.7 %.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.44 no.12
• /
• pp.1-7
• /
• 2007

This paper proposes the design method based on the composite right/left-handed (CRLH) structure to miniaturize and enhance the rejection performance in the stopband. For realization, we used the 0-th order resonance point of the unbalanced case of the CRLH and the simple theory of Inverter. The proposed technique is validated by the performance predictions and experiments, and it is found out that the suggested method enables the sire reduction of over 65 % from the conventional filters such as the parallel coupled type.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37 no.8C
• /
• pp.637-644
• /
• 2012

In this paper, a new compact power divider is suggested. Instead of the quarter wavelength transmission line(TX-line)s for the branches of the conventional Wilkinson's power divider design method, we use our composite right- and left-handed(CRLH) TX-line zeroth order resonator(ZOR) bandpass filters of one twelfth wavelength and reduce the physical length of the power divider. Besides, the filters in the branches can secure the passband for power-division. To validate the proposed power divider, we take an L-band for millitary satellaite transponder as the test case and the performances of the circuit and full-wave simulation results with the CRLH properties of the structure are shown with the dispersion curve and E-field at the ZOR. The measurement is compared with the simulation results. Also, the size reduction effect by the proposed scheme is addressed

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.46 no.12
• /
• pp.59-64
• /
• 2009

In this paper, the design of a new bandstop filter with an ultra-wide stopband is proposed using the metamaterial CRLH-TL. Instead of conventional periodic structures and multi-staged CRLH-TLs, extremely small one-cell type is adopted to circumvent the setbacks of conventional filters such as the lengthened ${\lambda}_g/2$-resonator ones or alternating impedance lowpass filter, and relatively slow skirt. Besides, for a very broad stopband, a strong coupling structure including stepped impedances is suggested and the zero-order resonance is made for effective size-reduction. The validity of the proposed design is proven through the fabrication and measurement, showing the overall size less than ${\lambda}_g/10$, the stopband wider than 12 GHz, 0.7 dB of the insertion loss.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.19 no.12
• /
• pp.1462-1469
• /
• 2008

This paper proposes the design method based on the Composite Right/Left-Handed(CRLH) structure to miniaturize and enhance the rejection performance in the stopband of the bandpass filter for a VHF band($169{\sim}211\;MHz$). For realization, we used the 0-th order resonance point of the CRLH and the simple theory of Inverter as coupling. The proposed technique is validated by the performance predictions and experiments, (Insertion loss <2 dB, $S_{11}$< -15 dB, suppression of up to the 3rd harmonic) and it is found out that the suggested method enables the size reduction of around 60 % from the conventional filters such as the parallel edge coupled type.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.19 no.2
• /
• pp.95-101
• /
• 2008

This paper presents a novel bandpass filter design method for suppressing spurious response in the GSM band and effectively reducing the overall size with the unbalanced-conditioned metamaterials. Compared to the conventional bandpass filters based on half-or quarter-wave resonators, the CRLH(composite right/left-handed) bandpass filter works excellently in harmonic-suppression by 40$\sim$50 dB and 80 %-miniaturization using the zero-order resonators bridged by Inductive-coupling Inverters suggested first time. The proposed technique, with the equivalent circuit and dispersion diagram, is validated by performance predictions and experiments.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
• /
• v.20 no.2
• /
• pp.59-67
• /
• 2009

본고를 통해 초고주파 이론과 공학 분야는 물론 물리학, 재료공학의 기초 학문 분야에서도 지대한 관심을 모으고 있는 Metamaterial(MTM) 구조에 대해 조명하고자 한다. 먼저 MTM의 핵심이라고 할 수 있는 Left-Handedness(LH) 왼손 전파 법칙과 LH 발생 재질인 Double Negative(DNG) 재질에서의 전파 특성을 상대 유전율과 상대 투자율 평면에서 확인하고, 일반 매질인 Double Positive(DPS)형인 오른손 전파 법칙 Right-Handedness(=RH) 매질과의 결합(Composite Right-and Left-Hnaded=CRLH)에서 얻어지는 특징들을 살펴본다. 특히 DPS와 DNC의 결합에서 얻을 수 있는 음의 공진과 0차 공진(Zero-Order Resonance)을 언급하고 ZOR을 응용한 RF 부품의 소형화와 특성 개선사례를 소개한다. 또한, 안테나와 전자파 산란 특성에 MTM의 특수한 성질을 이용하여, 크기를 줄이거나 표면파를 억제하거나 혹은 방사 개구를 확대 또는 렌즈 특성을 얻어낸 사례도 언급된다 그리고 LH 특성은 아니지만 MTM 계열인 ENG(Epsilon Negative), MNG(Mu Negative), ENZ(Epsilon Near Zero)를 응용한 예들을 보이고, MTM 관점에서 FSS(Frequency Selective Surface )의 특성을 논의하고, 그간에 발표된 대표적 MTM 연구 결과에 대한 소개를 마치고자 한다.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.26 no.1
• /
• pp.54-63
• /
• 2023

In this paper, a VHF band conformal antenna for UAV mounting was developed. The proposed antenna was designed as an shape-adaptive structure by minimizing the antenna height to be advantageous in RCS reduction performance. As for the antenna radiator, the outer radiator was arranged around the inner radiator to apply the CRLH zeroth-order resonance structure. With this structure, the height of the antenna was minimized, and it was reduced by about 70 % compared to the existing blade antenna. In addition, for impedance matching, the intermediate frequency bandwidth of the VHF band was improved through the sleeve pin of the inner radiator, and the low frequency bandwidth of the VHF band was improved by applying an EMI shielding gasket to the shorting pin of the outer radiator. The proposed antenna was manufactured and measured to verify the performance of the device and the performance after UAV mounting. As a result, the standard was satisfied for the operating frequency.

• Journal of Satellite, Information and Communications
• /
• v.12 no.1
• /
• pp.94-100
• /
• 2017

In this paper, we suggest a design method of a metamaterial-based low-profile antenna working at 425 MHz for LEO/Cube satellites. Satellites play an important role in linking th remote nodes in a wireless communication network and covering wide areas of the globe. Especially, an increasing number of universities or individuals aspire having their own satellites and build low-budget structures such as cube satellites in LEO and the ways to reduce the sizes of their satellites. Since the antenna occupies a major portion of the satellite surface, the antenna should be miniaturized for lighter weight. The proposed metamaterial low-profile antenna, unlike the conventional patch antenna, produces such a zeroth-order resonance to create an omnidirectional radiation pattern. Also, it is connected to a UHF waveguide bandpass filter as the feeding system to examine the possible change in the situation that the antenna is combined with the system. The performances of the monopole and proposed metamaterial antennas are compared to one another.