• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.47 no.1
• /
• pp.84-90
• /
• 2010

In this paper, a novel voltage-controlled oscillator (VCO) using the harmonic control circuit based on the composite right/left-handed (CRLH) transmission lines (TLs) is presented to reduce the phase noise without the reduction of the frequency tuning range and miniaturize the circuit size. The phase noise is reduced by the novel harmonic control circuit having the short impedances for the second- and third-harmonic components. The proposed harmonic control circuit is designed by using the CRLH TLs with the dual-band characteristic by the frequency offset and phase slope of the CRLH TLs. The high-Q resonator has been used to reduce the phase noise, but has the problem of the frequency tuning range reduction. However, the frequency tuning range of the proposed VCO has not been reduced because the phase noise has been reduced without the high-Q resonator. The miniaturization of the circuit size is achieved by using the CRLH TLs instead of the conventional right-handed (RH) TLs. The phase noise of VCO is -119.17 ~ -117.50 dBc/Hz at 100 kHz in the tuning range of 5.731 ~ 5.938 GHz.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.45 no.8
• /
• pp.35-40
• /
• 2008

This paper proposes a dual-band balun which is based on Wilkinson power divider. By inserting $\lambda/2$ transmission line between port 2 and 3, this balun shows good matching at all ports and improved isolation. We use matamaterial(CRLH, D-CRLH) structure for a miniaturization of the circuit implementation and dual-band operation at TDMB frequency range(195MHz) and DVB-H frequency range(670MHz). The proposed balun is designed with return loss larger than -12.98dB at all port, and isolation larger than -12.4dB, the amplitude imbalance between output signals less than 0.08dB, also phase differences of outputs less than $2.8^{\circ}$.

• Journal of Electrical Engineering and Technology
• /
• v.10 no.1
• /
• pp.331-337
• /
• 2015

A novel fully-printed microstrip antenna with negative first resonance and dual polarization is proposed. The radiator is printed on the 1-layer substrate instead of multilayers. The -1st resonance results from a composite right- and left-handed(CRLH) structure that has a circumferentially interlocked gap capacitively coupling a patch with a shorted-ring. This compact antenna is provided with a dual-polarization capability by creating two orthogonal linear polarizations in one body with coaxial feeds. The design is carried out by doing full-wave EM field simulation which is compared with the measurement of the fabricated antenna prototype. The measured results give the gain of 5 dBi and the efficiency of 78% at the -1st resonance mode as the center frequency of a downlink channel of the bandwidth over 20 MHz with 29 dB polarization isolation for mobile communication.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.60 no.12
• /
• pp.2299-2304
• /
• 2011

In this paper, we propose the methodology to make the bandpass filters for the Smart Grid IED(Intelligent Electronic Device) smaller than the conventional bandpass filters. The size-reduction of the filters and the filter performances are indebted to devising small CRLH(composite right- and left-handed) resonators and coupling them as the metamaterial structures. The design methodology is validated by the equivalent circuit to be compared with the reliable full-wave EM simulation, and the proposed metamaterial filter outperforms the standard parallel-edge coupled filter with respect to the miniaturization and frequency response.

• Journal of electromagnetic engineering and science
• /
• v.12 no.4
• /
• pp.280-286
• /
• 2012

The conventionally classified waves are reclassified in this paper, including the waves associated with metamaterial (MTM) transmission lines. Various types of guided waves in periodic structures are analyzed for 1D Composite Right/Left Handed (CRLH) transmission lines (TL). In addition, dispersion diagrams for 1D CRLH, RH, and LH TLs are presented in terms of radiation conditions. We have refined the design equations of the conventional 1D CRLH TL and proposed a condition to realize the desired phase shift and its slope per unit cell. This condition has been applied to the conventional Wilkinson power divider and realized into MTM added $90^{\circ}$ hybrid coupler. Based on the 10 dB return loss and the $90{\pm}10^{\circ}$ phase shift, the bandwidths of the MTM added $90^{\circ}$ hybrid coupler are 82.25% and 103.5% against the conventional 23% and 52.5%, respectively.

• ETRI Journal
• /
• v.35 no.1
• /
• pp.150-153
• /
• 2013

In this letter, a compact and fully printed composite right- and left-handed (CRLH) dual-band power divider is proposed. The branches of the conventional Wilkinson power divider are replaced by subwavelength CRLH phase-shift lines having $+90^{\circ}$ for one frequency and $-90^{\circ}$ for another frequency for dual-band and miniaturization performance. Equations are derived for the even- and odd-mode analysis combined with the dual-band CRLH circuit. A PCS and a WLAN band are chosen as the test case and the circuit approach agrees with the CAD simulation and the measurement. Additionally, the CRLH property is shown with the dispersion diagram and the eightfold size reduction is noted.

• Journal of Electrical Engineering and Technology
• /
• v.11 no.2
• /
• pp.463-469
• /
• 2016

In this paper, the use of a dual composite right/left-handed coplanar waveguide (CPW) transmission line is proposed for the design of a band rejection filter. The notch property of the filter is achieved by combining the convex signal line with the shorted concave meander line, and the equivalent circuit model is extracted from the geometry of the unit cell for organizing the band rejection property. Then the equivalent parameters of the unit cell are analyzed to identify those behaviors. And the dispersion characteristics and energy distributions are simulated. In the end, the band rejection filter is manufactured by cascading two proposed unit cells. We show that the measurement result for the resonant frequency demonstrates good agreement with the simulation result and the band rejection filter provides a rejection performance of 17.5 dB at the stopband frequency ranging from 869 MHz to 894 MHz.

• Journal of electromagnetic engineering and science
• /
• v.13 no.3
• /
• pp.141-150
• /
• 2013

Multiplexers based on isolation circuits made of metamaterial lines are proposed and studied. The new approach provides unique advantageous features beneficial to system designer. For instance, there is no need to modify the filters used in multiplexers. Also, the design process is straightforward. In this paper, two types of multiplexers based on metamaterial isolation circuits are presented, and their operation concepts are explained. Also, theories and design process of isolation circuits are presented to help readers design and fabricate proposed multiplexers. For verifying the concepts, two types of triplexers and two types of quadruplexers are designed and fabricated. All filters used in the multiplexers are commercial surface acoustic wave filters. The measured results are well matched with the simulation results.

• ETRI Journal
• /
• v.36 no.1
• /
• pp.151-154
• /
• 2014

A novel frequency-switchable antenna that uses PIN diodes and a composite right- and left-handed transmission line (CRLH TL) is proposed. The CRLH TL provides multi-order resonance, including a zeroth-order resonance (ZOR), and its shunt stub determines the ZOR frequency. Thus, the resonant frequency is arbitrarily chosen by lumped chip inductors on the shunt stub. Two prototypes are designed using different chip inductors while maintaining the antenna geometries. Antenna #1 can switch the resonant frequency from 1.8 GHz to 2.3 GHz. Antenna #2 can switch its resonance from 0.9 GHz to 2.3 GHz.

• Journal of electromagnetic engineering and science
• /
• v.11 no.4
• /
• pp.290-297
• /
• 2011

Recent progresses in the live electrooptic imaging (LEI) technique are reviewed with emphasis on its functionality of real-time visual accesses to traveling electric waves in the GHz range. Together with the principles, configurations, and procedures for the visual observation experiments by an LEI camera system, the following results are described as examples indicating the wide application ranges of the technique; Ku-band waves on arrayed planar antennas, waves on a Gb/s-class digital circuit, W-band waves traveling both in slab-waveguide modes and aerially, backward-traveling wave along composite right/left-handed transmission line, and, waves in monolithic microwave integrated circuit module case.