• Journal of Advanced Navigation Technology
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• v.21 no.1
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• pp.84-89
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• 2017

This paper presents a dual-wideband bandpass filter (BPF) with high band-to-band isolation and skirt selectivity using distributed composite right/left-handed (CRLH) transmission line (TL) quad-mode resonators (QMRs). The results of the proposed distributed CRLH TL unit cell analysis are used to establish the scattering parameters and the resonance frequencies of the QMR constituting the dual-wideband BPF. A novel dual-wideband bandpass filter is designed and fabricated, using the derived scattering characteristics. The measured results show that the fabricated dual-wideband bandpass filter has an insertion loss of less than 1.08dB in the lower band, and of 2.01dB in the upper band, a bandwidth of 2.8-5.52GHz and 9.68-12.26GHz, and a band-to-band isolation of more than 38dB, from 6.34-8.42GHz.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.1
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• pp.245-252
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• 2018

In this paper, the dual band circular polarization patch antenna was designed by using band rejection characteristics of CSRR structure for geostationary satellites. A quadrangular CSRR structure was etched on the ground at the rear of the patch antenna's feed to obtain band rejection characteristics in between the receiving frequency band(1525~1559MHz) and transmission band(1626.5~1660.5MHz), and the corner of the patch antenna was truncated to enable circular polarization. It was confirmed that the resonant frequency of the patch antenna differs according to the size anc location of the CSRR and cirular polarization characteristics with simulation and measurement results. Measurement results shows the gain of about 0.2dB and 1.5dB in the TX and RX band.

• Journal of electromagnetic engineering and science
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• v.11 no.3
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• pp.143-151
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• 2011

This paper presents a survey of recent wireless power transfer systems. The issue of wireless power transfer is to achieve a highly efficient system with small positioning errors of the facilities setting. Several theories have been presented to obtain precise system design. This paper presents a summary of design theory for short range power transfer systems and detailed formulations based on a circuit model and an array of infinitesimal dipoles. In addition to these theories, this paper introduces a coil array scheme for improving the efficiency for off axis coils. In the microwave range, tightly coupled resonators provide a highly efficient power transfer system. This paper present san-overlay resonator array consisting of half wavelength microstrip line resonators on the substrate with electromagnetically coupled parasitic elements placed above the bottom resonators. The tight couplings between the waveguide and the load resonator give strong power transmission and achieve a highly efficient system, and enables a contact-less power transfer railroad. Its basic theory and a demonstration of a toy vehicle operating with this system are presented. In the last topic of this paper, harmonic suppression from the rectenna is discussed with respect to acircular microstrip antenna with slits and stubs.

• Journal of IKEEE
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• v.16 no.2
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• pp.121-126
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• 2012

In this paper, a push-push VCDRO (Voltage Controlled Dielectric Resonator Oscillator) with a modified frequency tuning structure is investigated. The push-push VCDRO designed at 16GHz is manufactured using a LTCC (Low Temperature Co-fired Ceramic) technology to reduce the circuit size. The frequency tuning structure is embedded in intermediate layer of A6 substrate by an advantage of LTCC process. Experimental results show that the fundamental frequency suppression is above 30dBc, the frequency tuning range is 0.43MHz over control voltage of 0 to 12V, and phase noise of push-push VCDRO presents a good performance of -103dBc/Hz at 100KHz offset frequency from carrier.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.12
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• pp.1706-1711
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• 2013

This paper presents the filter of a resonator comprising a shorted open gap ring(SOGR) and interdigital lines. The proposed filter has the ultra wideband characteristic operating from 3 GHz to 10.5 GHz. In order to achieve the remarkable improvement in the size-reduction of the overall filter structure, only one cell of the SOGR with the inter-digital lines is adopted. It is shown that this filter has the size of $18mm{\times}15mm$ using a metamaterial, the fractional bandwidth over 100%, the insertion loss much less than 1dB, an acceptable return loss performance in the results.

• 한국ITS학회:학술대회논문집
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• v.2006 no.10
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• pp.187-190
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• 2006

In this paper, the equivalent circuit of tapped-line that is applied in the feeding of the band-pass filter with high coupling is suggested and the value of an equivalent circuit is mathematically defined. An equivalent circuit of tapped-line is composed by open stub and additional transmission line, and the electrical lengths of stub and line can be obtained by the impedance of resonator and the inverter. The new equivalent circuit of tapped-line can be simply applied of design of band-pass filter and leads to very good agreement compared with theoretical value. The coupled-line band-pass filter using equivalent circuit of tapped-line shows the insertion loss of 1.97 dB and the return loss of 18.5 dB at the center frequency of 5.8 GHz.

• Korean Journal of Optics and Photonics
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• v.13 no.4
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• pp.295-300
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• 2002

We developed an optical transmitter and receiver for an electrical time division multiplexed (ETDM) 20 Gb/s optical transmission system, and experimentally investigated their characteristics. Especially, the clock extraction circuit, which is a key component in realizing broadband optical transmission receivers, was realized by using an NRZ-to-PRZ converter implemented with a half-period delay line and an EX-OR, a high-Q bandpass filter using a cylindrical dielectric resonator, and a microstrip coupled-line bandpass filter. Finally, the bit-error-rate of demultiplexed 10 Gb/s electrical signal after back to-back transmission was measured, and a high receiver sensitivity [-26.2 dBm for NRZ ($2^{7}-1$) pseudorandom binary sequence (PRBS)] was obtained

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.9
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• pp.888-895
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• 2004

This paper proposes new miniaturization method of parallel coupled line filter by using capacitors and grounding. Proposed method can reduce resonator size by using only a small number of capacitor and grounding of parallel coupled line filter which is conventional in field of RF filters because of its design and fabrication simplicity. This paper applies the miniaturization method of transmission line and parallel coupled line to parallel coupled line filter, and presents that grounding can reduce the number of shut capacitors. Presented miniaturized method has merits of miniaturization of parallel coupled line, harmonic suppression, and improvement of high frequency skirt with harmonic suppression. For verification of proposed method, this paper presents a hairpin filter, which has 900 MHz center frequency and 10 % FBW, miniaturized to λ/4 by proposed method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.3
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• pp.236-244
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• 2010

In this paper, a planar structure negative group delay circuit(NGDC) is proposed to overcome the limited availability of the component values required for the prototype lumped element(LE) NGDC design. From the prototype LE circuit analysis, general design equations and the conditions to obtain the NGD are derived and illustrated. Then the LE circuit is converted into the planar structure by applying the transmission line resonator(TLR) theory. As a design example, the LE NGDC and the proposed planar structure NGDC are designed and compared. To estimate the commercial applicability, 2-stage reflection type planar NGDC with -5.6 ns of total group delay, -0.2 dB of insertion loss, and 30 MHz of bandwidth together with 0.1 dB and 0.5 ns of the magnitude and group delay flatness, respectively, for Wideband Code Division Multiple Access(WCDMA) downlink band is fabricated and demonstrated. Also, to show the applicability of the proposed NGDC, we have configured a simple signal cancellation loop and obtained good loop suppression performance.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.6
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• pp.946-951
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• 2000

In this paper, we showed the characteristic of transmission line with DCS (Defected Ground Structure), which is etched on the metallic ground plane. And we extracted the equivalent element value of DGS section. Effects of a lumped element placed on DGS section were investigated by employing DGS of dumbbell shape and parallel resonator with DGS. Chip type resistor, inductor, and capacitor were chosen as lumped elements for experiments. Experimental results show that the Q-factor and resonant frequency of the proposed DGS section can be controlled directly by using the external lumped element.