• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.6
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• pp.117-124
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• 2015

In this paper, a new kind of wideband, low-loss composite right/left-handed (CRLH) transmission line (TL) and a Wilkinson power divider are presented. The TL is composed of a parallel meander inductor and a series cutting capacitor based on coplanar waveguide (CPW) structure. The power divider is designed by substituting the CRLH-TL into the conventional transmission line. The experiment results show that the TL has a good agreement with the desired results, exhibiting the return losses under 12 dB from 8.4 GHz to 34.4 GHz. The operating frequencies of the power divider are 12.05 GHz to 13.15 GHz and 16.50 GHz to 19.30 GHz, respectively. The 20 dB bandwidths are 8.9 % and 17.9 %, respectively. Typical experimental measurements are conducted and compared with the simulated results.

• ETRI Journal
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• v.32 no.3
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• pp.472-474
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• 2010

In this letter, a novel zeroth-order resonant (ZOR) antenna on vialess co-planar waveguide (CPW) is proposed. It is based on a composite right/left-handed CPW transmission line. To achieve a compact size, this antenna utilizes the ZOR condition, and its reactive parameters determine the resonant frequency. Each unit cell is composed of a metallic top patch and meander lines. Since it is realized on the CPW single layer, the proposed antenna has the benefits of being a compact size and easy to fabricate. The bandwidth of 6.8% and efficiency of 62% are experimentally achieved. Its bandwidth is enhanced compared with other ZOR antennas.

• Journal of information and communication convergence engineering
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• v.11 no.3
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• pp.147-152
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• 2013

A novel balun being the structure of a Wilkinson power divider is suggested and fabricated. One of the power dividing paths in the suggested balun uses a conventional ${\lambda}/4$ transmission line for $-90^{\circ}$ phase shifting, and the other path uses a composite right/left-handed -${\lambda}/4$ transmission line for $+90^{\circ}$ phase shifting with four series capacitors and three parallel inductors. In addition, the suggested balun uses two $50-{\Omega}$ resistors and a conventional $50-{\Omega}$ transmission line of ${\lambda}/2$ electrical length between the two output ports, achieving good isolation and reflection values of two balanced ports. The suggested balun is simulated by the advanced design system simulation program and fabricated on TLX-9 20-mil substrate. The fabricated balun has a very good values of $S_{11}$ = -27.46 dB, $S_{21}$ = -3.40 dB, and $S_{31}$ = -3.28 dB, a phase difference of $-179.5^{\circ}$, a magnitude difference of 0.12 dB, and a delay difference of 0.1 ns, with $S_{22}$ = -36.28 dB, $S_{33}$ = -27.19 dB, and $S_{32}$ = -25.2 dB at 1 GHz, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.1
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• pp.21-28
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• 2012

In this paper, we propose a flexible zeroth-order resonant(ZOR) antenna. Its zero phase constant ensures that the antenna performance is independent of substrate deformation. A composite right/left-handed transmission line is designed based on coplanar waveguide technology to realize the zeroth-order resonance phenomenon. The CRLH is an implementation of metamaterial(left handed material) which is composed of shunt inductance and series capacitance. In order to yield additional circuital parameter, chip inductor and gap capacitor is added, respectively. The proposed ZOR antenna provides good performances: reasonable bandwidth(6.5 %) and peak gain(0.69~1.39 dBi). Simulated and measured results show that the antenna's resonant frequencies and radiation patterns are almost unchanged at different curvature diameters of 30, 50, 70 mm, as well as for a flat surface.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.2
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• pp.223-230
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• 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
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• v.44 no.7 s.361
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• pp.1-6
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• 2007

In this paper, the spiral zeroth-order resonance (ZOR) antenna using composite right- and left-handed (CRLH) transmission line is proposed. The zeroth-order resonant characteristics of the antenna are described by dispersion relation of a periodic structure. The size of the $2{\times}2$ spiral ZOR antenna is $0.155{\lambda}_{0}{\times}0.155{\lambda}_{0}$. By increasing shunt inductance of CRLH transmission line, the size of this antenna is reduced by 65% compared with that of a mushroom ZOR antenna. The radiation pattern of this antenna have omnidirectional pattern which is similar to that of mushroom ZOR antenna.

• Journal of electromagnetic engineering and science
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• v.11 no.2
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• pp.76-82
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• 2011

In this paper, a novel design for a dual-band negative group delay circuit (NGDC) is proposed. Composite right/left-handed (CRLH) ${\lambda}/4$ short stubs are employed as a dual-band resonator. A CRLH ${\lambda}/4$ short stub is composed of a typical transmission line element as the right-handed component and a high-pass lumped element section as the left-handed component. It is possible to simultaneously obtain open impedances at two separate frequencies by the combination of distinctive phase responses of the right/left-handed components. Negative group delay (NGD) can be obtained at two frequencies by using dual-band characteristics of the CRLH stub. In order to achieve a bandwidth extension, the proposed structure consists of a two-stage dual-band NGDC with different center frequencies connected in a cascade. According to the experiment performed, with wide-band code division multiple access (WCDMA) and worldwide interoperability for microwave access (WiMAX), NGDs of $-3.0{\pm}0.4$ ns and $-3.1{\pm}0.5$ ns are obtained at 2.12~2.16 GHz and 3.46~3.54 GHz, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.9
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• pp.912-918
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• 2011

In this paper, a composite right-/left-handed(CRLH) rectangular waveguide satisfying a balanced condition above the cut-off frequency is presented. The proposed structure consists of one shorted stub and two twisted H-plane irises which produce an effectively negative permeability and permittivity, respectively. The CRLH structure can independently control the series and shunt resonance frequencies of a CRLH transmission line which determine the left-handed(LH) and right-handed(RH) bands due to a minimized coupling between a shorted stub and twisted H-plane irises. Thus, the design of the CRLH waveguide satisfying a balanced condition is possible. To analyze the CRLH structure, a crossly connected equivalent circuit is derived. The simulated and measured results confirm that the proposed CRLH waveguide has a transmission property without a band gap among the LH and RH bands.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.9
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• pp.1042-1047
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• 2012

In order to obtain balanced ports matching and isolation between balanced ports of a Marchand balun, a compact isolation network is proposed. The proposed compact isolation network is designed using composite right/left-hand (CRLH) transmission line and compact phase inverter using CRLH transmission line unit cell. Also, design method and analysis of proposed isolation network are presented. The sizes of the proposed isolation networks are significantly reduced to $0.11{\lambda}_g$ and $0.07{\lambda}_g$ compared with the conventional isolation network of $0.5{\lambda}_g$. The Marchand balun is operated at 2.45 GHz and is demonstrated through excellent experimental results.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.11
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• pp.2032-2037
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• 2010

This paper describes a design of dual band amplifier using left handed (LHJ) transmission line, which is a part of composite right/left handed (CRLH) transmission line. It is well known that CRLH transmission lines show dual band frequency response. At first, two single-band amplifiers for frequency f1 and f2 are designed, and their matching networks at both amplifiers are synthesized into the dual band matching network by adopting CRLH structure. As an example for proving the validity of the proposed design, a dual band amplifier operating at 1800MHz and 2300MHz is designed, fabricated and measured. The simulation and measurement show that the proposed amplifier operates well at the desired dual bands with the gain of 13.65dB and 19dB at 1850MHz and 2360MHz, respectively, and a good matching performances. In addition, a quite good agreement between the simulation and measurement is observed.