• Transactions on Electrical and Electronic Materials
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• v.7 no.1
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• pp.42-50
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• 2006

Co-Fe-Al-O nano-granular thin films with high electrical resistivity, fabricated by radio frequency magnetron sputtering under an $Ar+O_2$ atmosphere, are found to show good soft magnetic properties in the GHz frequency range. The real part value of the relative permeability is 260 at low frequencies and this value is maintained up to the GHz frequency range. A non-integrated type noise filter on a coplanar waveguide transmission line is demonstrated by using the Co-Fe-Al-O nano-granular thin film with the dimensions of $4\;mm(l){\times}4\;mm(w){\times}0.1\;{\mu}m(t)$. The insertion loss is very low being less than 0.3 dB and this low value is maintained up to 2 GHz. At a ferromagnetic resonance frequency of 3.3 GHz, the degree of noise suppression is measured to be 3 dB. This level of noise attenuation is small for real applications, but there is much room for further improvement by increasing the magnetic volume and integrating the magnetic thin film into the CPW transmission line.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.11
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• pp.91-99
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• 1998

A 5Gbps LiNbO$_3$ optical phase modulator was designed, packaged and it's properties were characterized for optical communications. The APE(annealed proton exchange) method was employed for the optical waveguide and the electrode of ACPS (asymmetric coplanar strip) type was formed by electro-plating on LiNbO$_3$ for applying microwave signal with a dimension of width 18${\mu}{\textrm}{m}$, gap 9${\mu}{\textrm}{m}$ and length 50mm. The fabricated single-moded modulator operated at a 1550nm wavelength exhibits its modulation bandwidth, insertion loss and driving voltage of 7㎓, 3.0dB and 6V, respectively.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.11
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• pp.40-46
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• 2002

A MEMS(Micro Electro Mechanical System) package using a doped-silicon(Si) carrier for coplanar microwave and millimeter-wave integrated circuits is proposed in order to reduce parasitic problems of leakage, coupling and resonance. The proposed carrier scheme is verified by fabrication and measuring a GaAs CPW(Coplanar Waveguide) on the three types of Si-carriers(gold-plated high resistivity, lightly doped, high resistivity). The proposed MEMS package using the lightly doped(15 ${\Omega}{\cdot}$) Si-carrier shows parasitic-free performance since the lossy Si-carrier effectively absorbs and suppresses the resonant leakage.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.9
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• pp.1782-1792
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• 1994

Ti : $LiNbO_3$ traveling-wave phase optical modulators at wavelength 1.3㎛ have been designed and fabricated, focusing on the optical waveguide and asymmetric coplanar electrode structure. To improve the phase-mismatch of traveling-wave ACPS electrode, the characteristic impedance, effective microwave index, and electrode loss have been presented as a function of geometric parameters including electrode and buffer layer thickness. Low-loss channel optical waveguides on $LiNbO_3$ were fabricated by the Ti diffusion method with $O_2$ water-vapor environment. $2.5{\mu}m$ thick electrode was successfully fabricated by double-spin image reversal process. Modulation bandwidth was limited by a resonance at 2.9 GHz and modulation bandwidth up to 2.5GHz was approxirnately measured.

• 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.

• Journal of the Korean Magnetics Society
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• v.20 no.1
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• pp.18-23
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• 2010

Ferromagnetic resonance (FMR) measurement is an important experimental technique for the study of magnetic dynamics. We designed and set up the vector network analyzer ferromagnetic resonance (VNA-FMR) measurement system with home made coplanar waveguides (CPW). We examined 10-, 20-, 40-nm thick Py thin films to test the performance of the VNA-FMR measurement system. We measured S-parameter (transmission/reflection coefficient) of Py thin films on a CPW. Resonance frequency is investigated from 2.5 to 7 GHz for a field range from 0 to 490 Oe. The VNA-FMR data shows the resonance frequency increment when the external magnetic field increases. We also investigated Gilbert damping constant of Py thin film using resonance frequency (${\omega}_r$) and linewidth ($\Delta\omega$). After investigating dependence of thickness, we find that an decrease in S-parameter intensity as Py thin film thickness decreases. And the FMR results show that the effective saturation magnetization, $M_{eff}$, increase from 7.205($\pm$0.013) kOe to 7.840($\pm$0.014) kOe, while the film thickness varies from 10 to 40 nm.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.11
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• pp.15-20
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• 2004

This paper proposed a very simple method of extracting an effective permittivity from the data of scattering parameters measured on the transmission line of coplanar waveguides in the frequency range of microwave or millimeter waves. This is an extracting method of an effective permittivity $\varepsilon$$_{eff}$ in the case of $\beta$$\ell$ =n$\pi$ (n=integer), where the value of S$_{11}$ changes abruptly following the operating frequency. The experimental value of the effective permittivity $\varepsilon$$_{eff}$ on a dielectric substrate of Rogers 4003$^{TM}$ material of $\varepsilon$$_{r}$ =3.38 showed the value of 2.042, which differs in the error of -3.4% to 8% from those calculated from the previously reported formulae. This result showed that the measurement method was very simple, as well as applied directly to the fabricated circuit patterns, even though the circuit patterns might be complicated or on the substrate of different dielectric materials.s.als.

• Transactions on Electrical and Electronic Materials
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• v.13 no.5
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• pp.237-240
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• 2012

A conducting polymer, poly 3-hexylthiophene (P3HT) is characterized with the metal-insulator-semiconductor (MIS) measurement method and the high frequency planar circuit method. From the MIS measurement method, the relative dielectric constant of the P3HT film is estimated to be 4.4. For the high frequency planar circuit method, a coplanar waveguide is fabricated on the P3HT film. When applying +20 V to the CPW on P3HT film, the P3HT film is in accumulation mode and becomes lossy. The CPW on P3HT film is 1.5 dB lossier than the CPW on $SiO_2$ film without P3HT film at 50 GHz.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.101-106
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• 2005

This paper presents a new microwave oscillator incorporating a corrugated coplanar waveguide (CCPW) electromagnetic bandgap (EBG) structure as its terminating resonance component. The use of a compact CCPW EBG structure was effective in reducing the phase noise and improving the harmonic characteristics of the microwave oscillator circuit without additional backside processing and drastic size increment. The fully planar CCPW oscillator oscillating at the frequency of 5.41 GHz showed a phase noise characteristic of -90.7 dBc/Hz at 100kHz offset and a second harmonic suppression of 42.67 dB.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.303-306
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• 2005

In this paper, a CPW-fed monopole antenna using inverted L-type DGS structures is proposed and investigated experimentally. The proposed antenna is fabricated into FR4 substrate with dielectric constant($\varepsilon$r=4.5). Measured results show that the impedance bandwidth, determined from 10-dB return loss, for frequencies between 5.7250Hz-5.825CHz under the condition of VSWR$\leqq$2 is about 540MHg.