• ETRI Journal
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• v.27 no.3
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• pp.250-256
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• 2005

A novel planar polarization-agile microstrip subarray is proposed and its performance assessed by a thorough numerical investigation. The subarray consists of five square patches with a central element, directly coupled to a pair of microstrip feed lines by a cross-shaped aperture, which spreads the power outwards to the other patches through a network of suitable connections. By properly exciting the antenna at its input ports, any kind of polarization of the radiated field can be accomplished with fairly low cross-polarization levels. Moreover, since only two feed lines are required to drive the whole subarray, polarization agility is simply and attractively achieved by a single phase-shift circuit. The design concept is described and the results of the analyses and simulations performed by two completely independent full-wave approaches are presented and discussed.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.3
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• pp.75-79
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• 2008

Transmission line characteristics in microstrip line is used to in this paper. 5-microstrip lines composed of various spacing between them suggests characteristics of a diplexer in simulation. By applying the simiulation results, the diplexer realized shows better results of flat responses in bandpass characteristics and bandstop characteristics around 15 dB than symmetric spacing one.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.10
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• pp.1071-1077
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• 2002

In this paper, we have studied the dependence of insertion loss of the pressed microstrip PBG ring consisting of coupled two microstrip lines. When the distance decreases, two or three attenuation poles are created by the coupling between the lines. Thus the pressed PBG ring exhibits a wide stop band and sharp cutoff characteristics.

• ETRI Journal
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• v.31 no.6
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• pp.741-748
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• 2009

We present an analysis of microstrip coupled lines (MCLs) used to improve the stability of a 60 GHz narrowband amplifier. The circuit has a 4-stage structure implementing MCLs instead of metal-insulator-metal (MIM) capacitors for the unconditional stability of the amplifier and yield enhancement. The stability parameter, U, is used to compare the stability of MCLs with that of MIM capacitors. Experimental results show that MCLs are more stable than MIM capacitors with the same capacitances as MCLs because the parasitic parallel resistances of MCLs are lower than those of MIM capacitors. Moreover, the bandwidth of an amplifier using MCLs is narrower than one using MIM capacitors because the parasitic series inductances of MCLs are higher than those of MIM capacitors.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.1187-1190
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• 2004

In this paper we analyze the reflection characteristics of a dielectric microstrip line with an open-end termination containing optically induced plasma region, which are analyzed by the assumption that the plasma is distributed homogeneously in the laser illumination. The characteristics impedances resulting from the presence of plasma are evaluated the transmission line model. To estimate theoretically the characteristic response of same systems in the time domain, the Fourier transformation method is evaluated. The reflection characteristics of time response in microwave systems have been calculated.

• Journal of Advanced Navigation Technology
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• v.17 no.6
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• pp.687-692
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• 2013

This paper presents a compact power divider using microstrip-slotline transition technology. By using the microstrip-slotline transition, the ${\lambda}/4$ transmission lines of the divider can be changed to two ${\lambda}/8$ transmission lines in the multilayer structure. In the microstrip-slotline transition, we have used via holes to make a short circuit at the microstrip line and embedded spiral configuration stubs to reduce the electrical length of an open circuit at the slotline end point. For validating the microstrip-slotline technique, we have simulated and implemented the power divider with embedded spiral and via hole configuration circuits at a frequency of 2 GHz. Good agreement between the simulation and the measurement results is obtained at the operating frequency.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.389-392
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• 1996

The recent development of high temperature superconducting epitaxial thin film offer great potential for planar passive microwave application such as ring resonator, filters, transmission lines, and antennas. This paper describes the fundamental properties of Microstrip Band-Pass Filter using HTS Thin Film and its application to microwave devices. In order to fabricate HTS microstrip multiple filters, We have grown laser ablated HTS thin films, patterned by photolithographic process and wet etching processes intro HTS microwave devices.

• ETRI Journal
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• v.33 no.3
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• pp.335-343
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• 2011

The pad pitch of modern radio frequency integrated circuits is in the order of few tens of micrometers. Connecting a large number of high-speed I/Os to the outside world with good signal fidelity at low cost is an extremely challenging task. To cope with this requirement, we need reflection-free transmission lines from an on-chip pad to on-board SMA connectors. Such a transmission line is very hard to design due to the difference in on-chip and on-board feature size and the requirement for extremely large bandwidth. In this paper, we propose the use of narrow tracks close to chip and wide tracks away from the chip. This narrow-to-wide transition in width results in impedance discontinuity. A step change in substrate thickness is utilized to cancel the effect of the width discontinuity, thus achieving a reflection-free microstrip. To verify the concept, several microstrips were designed on multilayer FR4 PCB without any additional manufacturing steps. The TDR measurements reveal that the impedance variation is less than 3 ${\Omega}$ for a 50 ${\Omega}$ microstrip and S11 better than -9 dB for the frequency range 1 GHz to 6 GHz when the width changes from 165 ${\mu}m$ to 940 ${\mu}m$, and substrate thickness changes from 100 ${\mu}m$ to 500 ${\mu}m$.

• ETRI Journal
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• v.19 no.2
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• pp.48-58
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• 1997

Using high quality high-$T_c$ superconducting (HTS) YBCO thin films, we designed and fabricated 3-pole, 5-pole, and 7-pole lowpass filters consisting of microstrip transmission lines and open-stub lines. We measured the microwave response of the filters in the temperature range of T=85 K to 27 K. AtT=30 K, the observed inband insertion loss was 0.14dB and 0.02dB for the 5-pole and 7-pole filters, respectively. The cut-off frequency was 4.7 GHz for the 5-pole filter and 7.9GHz for the 7-pole filter. To the authors' knowledge, the measured inband insertion losses are the best values reported so far for the open-stub line type HTS multipole lowpass filters. The skirt property of the 5-pole filter showed a large improvement over that of the 3-pole filter as predicted from the simulation. We found that, to obtain a stable performance, the HTS multipole lowpass filters should be operated at the temperatures between 60% and 70% of $T_c$.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.2
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• pp.139-143
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• 1988

A new measurement method of coupled transmission line characteristics is described. This method presents precision values of even-and odd-mode impedances as well as effective dielectric constants of symmetric parallel coupled microstrip lines from the scalar quantities obtained by transmission coefficients at two different resonance frequencies. Especially these values include dispersion effects in the measured frequency band. The measured impedances and effective dielectric constants of actually fabricated coupled lines on the Teflon substrates with low dielectric constants are good agreement with predicted values. And the experimental pass band characteristics of single section resonator by using previously designed coupled lines agree well with theoretical values.