• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.768-771
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• 2003

Nowadays, the study on the ceramic components and modules used in telecommunication system is being performed. Duplexer is the one of the most important components and has the role of dividing Rx and Tx signal. Duplexer including the FBAR is being done vigorously LTCC is used for package like SAW package, duplexer package. In our research, LTCC material is used for FBAR duplexer package and photo-lithography for the fine line phase shifter. The good characteristics, low loss and good isolation, of duplexer is obtained by the fine line phase shifter having high characteristic impedance of stripline.

• Journal of the Korean Ceramic Society
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• v.32 no.1
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• pp.25-30
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• 1995

The frequenc dependence of magnetic permeability($\mu$r) and dielectric constant($\varepsilon$r) in MHz-GHz frequency range and their relationships with microwave absorbing properties were investigated in sintered and composite Ni-Zn ferrites, respectively. It was confirmed that zero reflection condition was required the real parts of permeability and permittivity in sintered specimen, and the complex permeability, permittivity and dielectric loss tangent in composite specimen. The real part of permittivity varied with the replacement of nickel by manganese in sintered Ni-Zn ferrite. Therefore, we could control the matching frequency and matching thickness.

• Proceedings of the KIEE Conference
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• 1993.11a
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• pp.35-37
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• 1993

This paper shows that the presence of constant impedance loads and induction motors in power system's loading contents can lead to transient voltage instabilities during normal system manipulations such as switchings. The abnormal induction motor characteristics during system transients which initiate the voltage instabilities are illustrated. The influence of motor and network parameters, such as motor inertia mechanical load quantity and nature on the severity of the voltage instability are studied.

• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.233-236
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• 2002

This paper has been designed and fabricated C-type micro, high-performance solenoid RF chip inductors with the size of 1.58$\times$0.82r0.94m0. The high frequency characteristics of simulated results obtained by HFSS were compared to those of measured results obtained by RF Impedance/Material Analyzer (HP16193A). Although the simulated inductance values were two times larger than the measured values and there are discrepancies in SRFs between simulated and measured values, it was observed that tile Q-factor values for fabricated inductors could be predicted from the simulated values.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.8
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• pp.41-48
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• 1992

The characteristics of traveling-wave electrodes for high-frequency electroptic integrated devices are described from the view point of improvement of phase-matching based on the conformal mapping method. Specific calculations of the characteristic impedance, effective microwave index, and eletrode loss for asymmetric coplanar strip(ACPS) and coplanar waveguide(CPW) electrode structures are presented as a function of the geometric electrode parameters including the electrode thickness and buffer layer thickness. 5-10(x10S0-6Tm) thick Au-ACPS electrodes were successfully fabricated by electroplating and ECR etcher. The improvement of modulation bandwidth can be theoretically observed from the combination of electrode and buffer layer thickness.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.7 no.2
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• pp.178-185
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• 1996

In this paper, a theoretical analysis of a wide band distributed mixer using a dual-gate GaAs MESFET's(DGFET) is introduced. Based on low noise mixer mode(LNM) region modeling of DGFET, variation of g/sub m/ and conversion gain are presented versus bias. The distributed mixer is composed of drain and gate transmission line, m-derived image impedance matching circuits at each input and output port, and DGFET's. Through computer simulation, wide-band characteristics of designed distributed mixer are confirmed. And, it is certificated that LO/RF isolation between gate 1 and gate 2 is obtained more than 15dB.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.10a
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• pp.236-239
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• 2004

'Structural surface becomes an antenna.' This term, CAS, indicates antenna embedding in structural surfaces. The CAS is composed of several composite laminates and Nomex honeycombs, and microstrip antenna elements are inserted between layers with designed configurations. Constituent materials are selected considering electrical contributions as well as mechanical performances. Antenna design with adhesive films are impossible because cf their thin and rough distributions between honeycomb and substrate. Therefore, adhesive effects on antenna performances in CAS are experimentally investigated, CAS with targeted impedance and radiation characteristics are designed considering adhesive effects.

• Journal of KSNVE
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• v.8 no.1
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• pp.49-56
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• 1998

Although the fundamental resonance frequency of a Helmholts resonator is mainly determined by the volume of the resonator and the size of the hole, it is also affected by the position of the hole and the shape of the resonator. In this study, the inertial end corrections and the fundamental resonance frequencies of concentric pipe resonators are estimated for various positions of the hole and shapes of the resonator by using the 3-D analysis. For an effective noise reduction in concentric pipe resonators with several holes, an optimal spatial hole-distribution is proposed based on the calculated transmission loss for various hole-distributions and sizes of holes.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.5
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• pp.213-217
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• 2012

In this paper, we design dual-band microstrip antenna for IEEE 802.16e mobile WiMAX standard IEEE 802.11 WLAN band at the same time. To solve interference at the desired operating frequency band, impedance matching is improved and simple production method showed the characteristics of the omni-directional and compact size. The proposed structure is considered to bring the effect of the installation costs, and show the antenna for dual-band communication.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.5
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• pp.33-40
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• 1998

In this paper, a design of current-mode continuous-time filters for low voltage and low frequency applications using complementary bipolar current mirrors is presented. The proposed current-mode filters consist of simple bipolar current mirrors and capacitors and are quite suitable for monolithic integration. Since the design method of the proposed current-mode filters are based on the integrator type of realization, it can be used for a wide range of applications. Since the input impedance of simple bipolar current mirror is small, in this paper, negative feedback amplifier is used to realize is designed by cascade method. The cutoff frequency of the designed filter can be easily tunable by the DC controlling current from 60kHz to 120kHz. The characteristics of the designed current-mode filters are simulated and examined by SPICE using standard bipolar transistor parameters.