• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.5 s.96
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• pp.488-493
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• 2005

In this study, waveguide-to-CPW transitions were developed for integrating waveguide and MMIC at V-band. The finite element method for numerical analysis and repeated experiments were performed to propose two types of waveguide-to-CPW transition. Using quartz substrate, proposed structures were designed for low loss as well as broadband characteristics. These waveguide-to-CPW transitions showed a good reliability and insensitivity to matching precision, and they could be fabricated with lower cost than that of the conventional connectors. Proposed two types of the structure showed insertion loss less than 1.9 dB and return loss better than 14 dB from 53 GHz to 60 GHz except unwanted resonance region, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.5
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• pp.445-450
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• 2002

We analyzed and measured a CPW(coplanar waveguide)-to-microstrip right-angled transition. Asymmetric CPW-to-microstrip transitions show significant resonances by the slot mode generation at the discontinuities. The air-bridge just shifting the resonance frequency can not fundamentally suppress the occurrence of the slot mode. So, we proposed the structure using offset microstrip section to eliminate the resonance. The proposed structure may be useful for the application of multi-layed structure.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.12B
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• pp.1754-1757
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• 2001

In this paper, a R-band hybrid amplifier with the coplanar waveguide(CPW) and the photonic bandgap(PBG) structure is designed and fabricated. The PBG and the CPW techniques are simultaneously employed in amplifier to improve the power added efficiency(PAE) and the IMD(Intermodulation Distortion) in R-band. In this paper, the PBG structures are optimized to obtain matching network. The output impedance of amplifier and the input impedance of PBG are matched to minimize the return loss. The PAE and the IMD were improved 15% and 4.5dB compared with the conventional amplifier, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.2
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• pp.158-161
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• 2006

The purpose of this research is to establish the crosstalk characteristic of mm-wave Coplanar structure. The components in mm-wave CPW are classified to transmission devices, EM devices, and quasi - TEM devices. After design of these devices, we analyzed these CPW s electromagnetically using FDTD method, and suggested the corsstalk characteristic of mm-wave CPW. In oder to realize a CPW module up to 30 GHz-100 GHz band, we research on a technology of 3-dimensional mm-wave CPW, and GaAs substrate with ohmic lossy layer. As a result this research, we suggested the optimum crosstalk characteristic of mm-wave CPW, and improved the crosstalk quality of mm-wave CPW.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1632-1638
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• 2008

This paper presents a method to design CPW (coplanar waveguide) balanced amplifiers using the existing CPW wilkinson balun. In order to realize the required power dividing/combining structure for balanced amplifiers, the CPP wilkinson balun is adopted. The proposed CPW balanced amplifier has much better matching performances than the CPW single-ended amplifier. The measured frequency bands, where the input and output reflection coefficients are less than -10dB, are $1.2{\sim}2.75GHz$ and $1{\sim}3.25GHz$, respectively, while the CPW single-ended amplifier has severely bad ones.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.10
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• pp.65-70
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• 2008

We design and fabricate the 94 GHz Coplanar waveguide(CPW)-to-rectangular waveguide transition that is transmits signal smoothly between the CPW, which is a popular transmission line of the planar circuits, and rectangular waveguide for the 94 GHz transceiver system. The proposed transition composed of the unilateral fin-line taper and open type CPW-to-slot-line transition is based on the hard and inflexible sapphire for the flip-chip bonding of the planar MMICs using conventional MMIC technology. We optimize a single section transition to achieve low loss by using an EM field solver of Ansoft's HFSS and fabricate the back- to-back transition that is measured by Anritsu ME7808A Vector Network Analyzer in a frequency range of $85{\sim}105$ GHz. From the measurement and do-embedding CPW with 3 mm length, an insertion and return loss of a single-section transition are 1.7 dB and more an 25 than at 94 GHz, respectively.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.55-56
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• 2017

In this paper, a wideband loop antenna is designed using a CPW feeding method for indoor digital TV applications. The proposed loop antenna consists of a square loop and two circular sectors which connect the loop with central feed points, and the CPW feed line is inserted in the lower circular sector. The CPW feed line is designed to match with the 75 ohm port impedance for DTV applications, and the ground slots are etched in order to improve the impedance matching in the middle frequency region. The optimized antenna is fabricated on FR4 substrate, and the experiment results show that it operates in the frequency band of 463-1,280 MHz for a VSWR < 2, which assures the operation in the DTV band.

• ETRI Journal
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• v.28 no.5
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• pp.648-651
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• 2006

In this letter we present a right-angle-bent coplanar waveguide (CPW) which we developed for the application of the driver amplifier-integrated (DAI) 40 Gbps traveling wave electroabsorption modulated laser module. The developed CPW realized parallel progression of the radio frequency (RF) and light using a dielectric overlay structure and wedge bonding on the bending section. The measured $S_{11}$ and $S_{21}$ of the developed CPW were kept below-10 dB up to 35 GHz and -3 dB up to 43 GHz, respectively. These measured results of the CPW were in good agreement with the simulation results and demonstrated the applicability of the CPW to the 40 Gbps communication module.

• Korean Journal of Optics and Photonics
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• v.18 no.4
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• pp.235-240
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• 2007

A ceramic stem based TO package incorporating a coplanar waveguide feed-line has been proposed allowing for 10 Gbps grade data transmission. The frequency response of a cylindrical feed-line fer a conventional metal based TO package was first analyzed, and compared with that of the CPW feed-line used for a ceramic based package such as a butterfly package. For the case where a DFB LD chip is packaged to an LD module, the measured 3 dB frequency bandwidths for the conventional and proposed packages were 3.5 GHz and 7.8 GHz respectively, which agree well with the theoretical results obtained from the modeling based on the small signal equivalent circuits. Consequently, we proposed a novel ceramic based TO package with a CPW feed-line in ceramic material as a stem to improve the frequency characteristics of the conventional one. And, its performance was theoretically observed to confirm that the proposed package provides even wider frequency bandwidth compared to the conventional one.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.10
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• pp.924-930
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• 1998

In this study, we describe the properties of an electro-optical modulator with CPW(coplanar waveguide) electrode fabricated on $LiNvO_3$ optical waveguide, that is applicable to optical communications. These optical modulators have features that use a buffer layer to reduce velocity mismatch between microwaves and optical wave as well as employ CPW to improve impedance and propagation mode mismatch between the electrode and the external circuits. And an annealed proton exchange technique for obtaining low-loss optical waveguides and good reproducibility was employed. Taking into consideration the mentioned background, to achieve the lower driving voltage of optical modulator, we have re-disigned the longer interaction length. And their device properties are discussed also. As a result, fabricated optical modulators of good 10Gps operation and low voltage(5.6V of the halfwave lengfth voltage) at an $1.5{\mu}m$ wavelength are achived with good reproducibility.