• ETRI Journal
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• v.35 no.2
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• pp.344-347
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• 2013

This letter presents a compact dual-mode tri-band bandpass filter by using a short-circuited stub-loaded stepped-impedance resonator (SIR) and a short-circuited stub-loaded uniform impedance resonator. Also, a hairpin SIR geometry is introduced to miniature the size of this filter while maintaining excellent performance. The use of a short-circuited stub at the central point of the hairpin SIR can generate two resonant modes in two passbands. Its equivalent circuit structure is analyzed by using the even-odd mode theory. For demonstration purposes, a tri-band filter for the applications of the Global Positioning System at 1.57 GHz, Worldwide Interoperability for Microwave Access at 3.5 GHz, and wireless local area networks at 5.2 GHz is designed, fabricated, and measured.

• Journal of the Korea Institute of Military Science and Technology
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• v.4 no.2
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• pp.122-129
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• 2001

A characterization procedure for analyzing symmetric coupled MIS(Metal-Insulator-Semiconductor) transmission line is used the same procedure as a general single layer symmetric coupled line with perfect dielectric substrate from the extraction of the characteristic impedance and propagation constant for even- and odd-mode. In this paper, an analysis for a new substrate shielding symmetric coupled MIS structure consisting of grounded crossbar at the interface between Si and SiO2 layer using the Finite- Difference Time-Domain(FDTD) method is presented. In order to reduce the substrate effects on the transmission line characteristics, a shielding structure consisting of grounded crossbar lines over time-domain signal has been examined. Symmetric coupled MIS transmission line parameters for even- and odd-mode are investigated as the functions of frequency, and the extracted distributed frequency- dependent transmission line parameters and corresponding equivalent circuit parameters as well as quality factor for the new MIS crossbar embedded structure are also presented. It is shown that the quality factor of the symmetric coupled transmission line can be improved without significant change in the characteristic impedance and effective dielectric constant.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.8
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• pp.61-67
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• 2010

A characterization procedure for analyzing symmetric coupled MIS(Metal-Insulator-Semiconductor) transmission line is used the same procedure as a general single layer symmetric coupled line with perfect dielectric substrate from the extraction of the characteristic impedance and propagation constant for even- and odd-mode. In this paper, an analysis for a new substrate shielding symmetric coupled MIS structure consisting of grounded crossbar at the interface between Si and SiO2 layer using the Finite-Difference Time-Domain (FDTD) method is presented. In order to reduce the substrate effects on the transmission line characteristics, a shielding structure consisting of grounded crossbar lines over time-domain signal has been examined. Symmetric coupled MIS transmission line parameters for even- and odd-mode are investigated as the functions of frequency, and the extracted distributed frequency-dependent transmission line parameters and corresponding equivalent circuit parameters as well as quality factor for the new MIS crossbar embedded structure are also presented. It is shown that the quality factor of the symmetric coupled transmission line can be improved without significant change in the characteristic impedance and effective dielectric constant.

• Journal of the Korean Institute of Telematics and Electronics
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• v.9 no.2
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• pp.1-16
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• 1972

In this paper, the characteristics of linearly tapered strip-line filters, where the even-mode and odd-mode characteristic impedances vary linearly with the same degree along the lines, are analyzed. The Impedance parameters of linearly tapered coupled strip-line, which is made by connecting two linearly tapered unsymmetric coupled strip-lines In cascade and the I:no input and output terminals are made equal, are obtained. Using the above parameters, the Image parameters of linearly tapered coupled strip-line filters are derived. The result of analysis shows that the line length can be made shorter and also the stop-band width between the fundamental and second pass-band becomes wider, compared with the coupled strip-line filters which use uniform strip-lines. Furthermore, the difference of impedance levels in the fundsmental and second pass-band becomes larger with the degree of taper of the lines. This property is unique, in comparison with the case of uniform or exponentially tapered strip-line filters.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.6
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• pp.46-52
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• 1985

A theoretical study of mutual coupling effects between two H-plane coupled microstrip patch antennas is presented. The radiation resistance and slot capacitance of a single micro-strip patch are calculated. To investigate the mutual coupling effects, the even and odd mode characteristic impedance and effective dielectric constants are obtained using the coupled microstrip line model. The S-parameter matrix elements 511,512 are used to study the mutual coupling e(facts in S-band frequency ranges for various patch spacings. Theoretical results and measurements are in good agreement.

• Journal of electromagnetic engineering and science
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• v.3 no.2
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• pp.126-132
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• 2003

In this paper, a coupled-line type waveguide bandpass filter is newly proposed. The proposed bandpass filter configuration consists of magnetically coupled waveguide cavities. In order to show the background of the proposed waveguide bandpass filter, the general coupled line TEM bandpass filter theory, which means the coupled line filter with arbitrary coupled line length and impedance level, will be briefly introduced. Calculations for the even- and odd-mode wave impedance of a coupled line waveguide structure are achieved based on the normalized impedance concept for a broad-side coupled waveguides by using vector finite element method(VFEM) calculation. Measured result of an implemented coupled-line type waveguide filter is presented.

• Journal of Advanced Navigation Technology
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• v.20 no.4
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• pp.361-366
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• 2016

This paper presents an arbitrary impedance transformer with unequal split, based on S- to admittance parameter conversion. When compared even/ odd- mode analysis, the parameter conversion design method constitutes a simple design method to include phase delay information and arbitrary port impedances and asymmetrical configurations. To validate this design method, we designed a 50 to $12.5{\Omega}$ impedance transformer with a 3:1 unequal power split, at an operating frequency of 1 GHz. To implement the proposed impedance transformer, the low impedance transmission lines of calculated result are fabricated by the transmission line connected shunt open stub. Good experimental performances were obtained, in full agreement with simulated results.

• Journal of electromagnetic engineering and science
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• v.16 no.1
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• pp.13-18
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• 2016

This paper presents a design of an impedance transformer (IT) with high frequency selectivity characteristics. The frequency selectivity can be controlled by even- and odd-mode impedance of a shunt coupled transmission line (TL). For experimental validation, a 50- to $20-{\Omega}$ IT was implemented at a center frequency ($f_0$) of 2.6 GHz for the long-term evolution signal. The measured results were in good agreement with the simulations, showing a return loss higher than 19 dB over a passband bandwidth of 0.63 GHz (2.28-2.91 GHz) and good sharp frequency selectivity characteristic near to the passband. The series coupled TL provides a transmission zero at 5.75 GHz, whereas the shunt coupled TL provides three transmission zeros located at 2 GHz, 3.1 GHz, and 7.14 GHz.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.3
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• pp.416-420
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• 2008

This paper proposes a new method to improve signal characteristics at branches frequently met in system-level routing. We also introduce the numerical formula which can estimate the time delay due to branches and the simple design guideline for system-level routing. Finally, we propose the routing method which can eliminate the signal reflection for the case of one driver and two receivers (multi-drop topology).

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.387-390
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• 1998

We propose comb-line filter using SIR(Stepped Impedance Resonator) with two transmission line. The coupling structure of the filter is double coupled line where two coupled lines are linked with cascade. We find out the inverter function of the filter. using even and odd mode impedance. The merits of the filter are that first, we can design transmission zero point at any frequency that we wanted without using lumped elements : chip capacitors and inductors. Second, we can design small size filters. To validate the inverter function of the filter with double coupled line we designed and fabricated two-pole band pass filter with the proposed filter structure.