• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.4A
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• pp.408-416
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• 2010

A dumbbell-type CPW transmission-line structure has been proposed to improve the return loss of the transmission line between a driver IC and flip-chip-bonding VCSEL(Vertical Cavity Surface Emitting Laser) in a hybrid opto-electric circuit board(OECB). The proposed structure used a pair of dummy ground solder balls on the ground lines for flip-chip bonding of the VCSEL and designed the dumbbell-type CPW transmission line to improve reflection characteristics. The simulated results revealed that the return loss of the dumbbell-type CPW transmission line was 13-dB lower than the conventional CPW transmission line. A 4-dB improvement in the return loss was obtained using the dummy ground solder balls on the ground lines. The variation rate of the reflection characteristic with the variation of terminal impedances of the transmission line (at the output terminal of the driver IC and the input terminal of the VCSEL) is about ${\pm}2.5\;dB$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.8 s.99
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• pp.835-841
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• 2005

In this paper, a novel sized-reduced CPW(Coplanar Waveguide) balun is proposed. It has a crossing structure between signal line and ground planes of CPW transmission line for the $180^{\circ}$ phase inversion. The$3{\lambda}/4$ CPW transmission line is reduced to ${\lambda}/4$ in physical length while the electrical length is preserved to $270^{\circ}$ by the $180^{\circ}$ phase inverting structure, while the previous balun by Lim et at. has a long $3{\lambda}/4$ transmission section to from the Wilkinson divider structure having out of phase between output ports. In addition, the measured data which show the crossing structure has the wanted $180^{\circ}$ phase change is presented in this work.

• Journal of Advanced Navigation Technology
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• v.20 no.1
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• pp.59-64
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• 2016

This paper presents a high dividing ratio unequal dualband divider using coplanar waveguide (CPW) and shunt connected open stub transmission lines. In order to implement transmission lines for a dualband divider using design equations, the low impedance lines of divider can be realized a shunt connected open stub transmission line. Also, the high impedance lines are realized by CPW transmission lines. To certify the validity of an unequal dualband divider using CPW and shunt connected open stub transmission lines, the 10:1 unequal dualband divider is implemented at operating frequency of 1 and 2 GHz. Good experimental performance at each frequency are obtained, which are in good agreement with the simulated results.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.3
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• pp.445-450
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• 2017

In this paper, the directional coupler with half-power division is designed and fabricated by using the vertical coupling structure based on the CPW transmission-line. Even-mode and odd-mode of the vertical coupling structure can be analyzed by the conventional CPW-line and the CBCPW-line, respectively, with half thickness of the substrate. The directional coupler is designed by using the tefron substrate with the dielectric constant of 2.55 and the thickness of 0.76mm. Manufactured directional coupler has the center frequency of 2.45 GHz and the bandwidth of 66.1%. Also, the return loss and isolation are 19.52dB and 19.47dB, respectively, at the center frequency.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.11
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• pp.1518-1523
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• 2018

A method for designing a DDQYA fed by a CPW is proposed in this paper. The proposed CPW-fed DDQYA consists of two series-connected strip dipoles, a ground reflector, and a strip-pair director. Instead of the conventional microstrip feed line in which the signal line is located on the substrate opposite to the antenna, a CPW is used because CPW is located on the same side with the antenna, and so the fabrication is easy. The strip-pair director is composed of two horizontally-separated strips, and it is added above the second dipole to enhance the gain in the high frequency region. A prototype of the proposed CPW-fed DDQYA is fabricated on an FR4 substrate. The fabricated antenna has a frequency band of 1.66-3.38 GHz(68.3%) for a voltage standing wave ratio < 2, and measured gain ranges 5.0-7.3 dBi over a frequency band of 1.60-2.90 GHz.

• Journal of the Microelectronics and Packaging Society
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• v.10 no.2
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• pp.27-31
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• 2003

RF characteristics of CPW(coplanar waveguide) pattern with bonding pads used in flip-chip packaging of GaAs is studied in the frequency range of 1 GHz to 35 GHz. Simulation, fabrication and evaluation are performed for the proposed patterns. Measurement results show proposed patterns have similar properties of $S_{11}$below -31 dB and $S_{21}$ above -0.19 dB with typical CPW In addition RF properties are improved with the increase of width of ground line. This indicates CPW structure with bonding pads keeps RF characteristics of typical CPW.

• Proceedings of the KAIS Fall Conference
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• 2008.11a
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• pp.69-71
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• 2008

본 논문은 CPW 맴돌이형 공진기를 이용하여 설계한 발진기에 대하여 기술한다. 제안된 CPW 맴돌이형 공진기는 CPW 선로 주변과 접지면 사이에 다수개의 맴돌이 구조를 포함한다. 맴돌이형 공진기는 평면형 구조에서 비교적 높은 Q 값을 가지고 있기 때문에, 발진기의 출력뿐만 아니라, 위상 잡음 개선에도 좋은 영향을 끼친다. 또한 평면형 전송선로 구조이므로 마이크로스트립은 물론 CPW 구조로도 설계가 가능하다. 설계한 발진기를 실제로 측정하여 6.54GHz에서 3.98dBm의 출력 특성과 -118.1dBc/Hz @1MHz의 위상잡음 특성을 얻었다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.5
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• pp.285-289
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• 2003

This paper proposes a 10 ${\mu}{\textrm}{m}$ thick oxide air-bridge structure which can be used as a substrate for RF circuits. The structure was fabricated by anodic reaction, complex oxidation and rnicrornachining technology using TMAH etching. High quality films were obtained by combining low temperature thermal oxidation (50$0^{\circ}C$, 1 hr at $H_2O$/O$_2$) and rapid thermal oxidation (RTO) process (105$0^{\circ}C$, 2 min). This structure is mechanically stable because of thick oxide layer up to 10 ${\mu}{\textrm}{m}$ and is expected to solve the problem of high dielectric loss of silicon substrate in RF region. The properties of the transmission line formed on the oxidized porous silicon (OPS) air-bridge were investigated and compared with those of the transmission line formed on the OPS layers. The insertion loss of coplanar waveguide (CPW) on OPS air-bridge was (about 1 dB) lower than that of CPW on OPS layers. Also, the return loss of CPW on OPS air-bridge was less than about - 20 dB at measured frequency region for 2.2 mm. Therefore, this technology is very promising for extending the use of CMOS circuitry to higher RF frequencies.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.4 s.107
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• pp.380-386
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• 2006

Electric fuel sender fur the vehicle fuel gauge system was designed and fabricated based on the CPW(Co-Planer Waveguide) transmission line theory. It is applied on this system that characteristic impedance of RF transmission line can be varied by the surrounded material of the line. By the characteristic impedance owing the level of gasoline or diesel fuel in vehicle fuel tank, CPW line has corresponding reflected signal as much as changed impedance. Detected signal is amplified, and delivered to fuel indicator into cluster unit on dash board. Conventional floating mechanical buoy level gauge has several defects as low reliability and high break down rate by mechanical operation, and has not good linearity for the fuel level difference. CPW line with electric circuits are constructed on 1.6 mm thickness epoxy substrate, and measurement shows that this system has more accurate level and better linearity than conventional mechanical system. New electric fuel sender which has good productivity with long lifetime and low-in-cost by the SMT chip assembling could be replaced this system with conventional floating buoy system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.11
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• pp.1143-1148
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• 2003

The distortion of picosecond pulses caused by dispersion as it propagates along microstripline and CPW(Coplanar waveguide) is investigated and measured using time domain measurement. Especially, this study presents that the distortion of these lines is analyzed and compared considering the relation between the dispersion effect and cut-off frequency(f$\_$TE/) of fundamental TE mode for the substrate of line. To verify theoretical results, several samples of 50 $\Omega$ lines are fabricated on the two kind of substrates with the different values of f$\_$TE/. The propagation characteristics of picosecond Gaussian pulse on thess lines are simply measured using VNA(Vector Network Analyzer) with the time-domain analysis function.