• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.2 s.93
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• pp.161-166
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• 2005

The synthesis procedure of Marchand balun using planar coupled-line is presented. The design limitations of this type of balun have been described before its synthesis procedure. The balun has equi-ripple passband responses and balanced output without fourth balanced transmission line which is difficult to implement with conventional planar topology. As an example, 2:1 Marchand balun is designed and its momentum simulation result show good verification fur this methodology.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.7
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• pp.752-759
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• 2013

This paper presents a method for analyzing and designing an extremely miniaturized planar ring hybrid, using the combination of parallel and diagonally shorted coupled lines. In contrast to conventional miniaturized coupled line filters, it is proven that the required electrical length of transmission line can be largely reduced to even a few degrees, not only effectively suppressing the spurious passband but also approximately maintaining the same characteristic around the stable center frequency. A ring hybrid filter at center frequency of 1 GHz was fabricated on the FR4 epoxy glass cloth copper-clad plat (CCL) PCB substrate. The insertion loss of a ring hybrid filter with the die area of $30mm{\times}30mm$ is -4.68 dB. Simulated results are well agreed with the measurements.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.8
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• pp.368-374
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• 2002

In this paper, we introduce a procedure to obtain a equivalent circuit of comb-line band pass filter. By employing equivalent circuits of each asymmetrical coupled line. we composed the full equivalent circuit of comb-line bandpass filter and derived simple design equations for extracting each line's impedance. To show the validity of design equations, we simulated and fabricated a planar type comb-line bandpass filter, which has center frequency 1.8㎓, band-width 50㎒ and four resonators. The resulting filter is very compact, have broad stop band with the second pass band centered at four times the center frequency of the first pass band. The experimental results show exact performances of design specification.

• Journal of Navigation and Port Research
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• v.34 no.7
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• pp.543-552
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• 2010

Modified compact combline bandpass filters are proposed based on the miniaturized quarter-wave transmission line which is composed of the parallel coupled line and lumped capacitors. The electrical length of the parallel coupled line in a resonator, which determines the size of combline bandpass filters, is just $5^{\circ}$ or $7^{\circ}$, resulting in a compact circuit area. The designed combline bandpass filter also has a wide upper stopband by suppressing the spurious passbands, not moving. Measured results of two fabricated filters centered at 400MHz show good agreement with the theoretical predications.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.4
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• pp.261-266
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• 1998

In developing the high density memory device, the etching of fine pattern is becoming increasingly important. Therefore, definition of ultra fine line and space pattern and minimization of damage and contamination are essential process. Also, the high density plasma in low operating pressure is necessary. The candidates of high density plasma sources are electron cyclotron resonance plasma, helicon wave plasma, helical resonator, and inductively coupled plasma. In this study, planar type magnetized inductively coupled plasma etcher has been built. The density and temperature of Ar plasma are measured as a function of rf power, flow rate, external magnetic field, and pressure. The oxide etch rate and selectivity to polysilicon are measured as the above mentioned conditions and self-bias voltage.

• Journal of Electrical Engineering and information Science
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• v.1 no.2
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• pp.96-100
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• 1996

This paper describes a concrete method for computing characteristic impedances and effective dielectric constants of the microstrip coupled lines without and with a dielectric overlay. The frequency-independent spectral domain method is used for the analysis of these lines. This method is a powerful, accurate, and numerically efficient approach for planar transmission line structure. For designing the optimal directional coupler, the velocities of even and odd mode must be equal but velocities of these two modes are different in the conventional coupled line which is inhomogeneous. The results show that these two velocities can be almost same according to variations of structural and material parameters in terms of the overlay(superstrate).

• ETRI Journal
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• v.32 no.1
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• pp.148-150
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• 2010

This letter presents the design of a compact bandstop filter (BSF) operating at two frequencies. The proposed BSF consists of open-ended stepped impedance resonators (OSIR) and an end-shorted parallel-coupled microstrip line (E-PCML). The OSIRs are used to achieve the impedance-controlled stopband positions. The wide BSF bandwidths are achieved through enhanced coupling of the E-PCML. Explicit design guidelines are derived using a lossless transmission line model. To validate theoretical predictions, a prototype dual-band BSF operating at 900 MHz and 2,100 MHz with fractional bandwidths of 72% and 36%, respectively, is implemented in microstrip.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.6 no.3
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• pp.80-90
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• 1995

The scattering parameters of a microstrip single line, a right-angle bend and a coupled line are calculated using the multiport network model for the frequency range from 1 to 18 GHz. The single line is analyzed using the planar waveguide model. The right-angle bend is broken into two rectangular segments, and each segment is analyzed in a similar fashion as the single line. Impedance matrices corresponding to the two segments are combined by the segmentation method. In the analysis of elec- tromagnetic coupling of the coupled line, a new method is employed resulting in much less computation time than those previous methods involving Green's functions. A good agreement between the numerical results for the three structures and those from SuperCompact reveals the usefulness of the multiport network medel in analyzing complicated mirostrip single and coupled line discontinuities.

• Journal of information and communication convergence engineering
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• v.8 no.5
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• pp.489-492
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• 2010

This paper proposes the planar-type modified monopole antennas of loop structure. This antenna has an opened center of a conventional closed loop structure with an inside-folded terminal of the loop microstrip line. The size of the proposed antenna was minimized by folding the end of the loop. Also, the reactance value has been minimized by increasing capacitances between the coupled microstrip line. Therefore the proposed antenna has been compacted to about 20% from a conventional loop antenna and has increased its efficiency. The proposed antennas have an omni-directional pattern, the antenna gain was 3.67 [dBi] and the bandwidth was 900 MHz (2.6~3.56 GHz) with VSWR$\leq$2 from the simulated and the measured results. The frequency utilization coefficient was 29.9%. These properties could satisfy the S-DMB band.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2003.11a
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• pp.260-264
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• 2003

In this paper, a $\lambda/4$ hairpin resonator is proposed to reduce the size of planar resonators for a LTCC MLC bandpass filter. The $\lambda/4$ hairpin resonator operates as stepped impedance resonator (SIR) without changing the width of the planar resonator. It is composed of two sections those are parallel coupled line and transmission line. The characteristic impedance of two sections is different each other. The design formulas of the bandpass filter using the coupling element at the arbitrary position are derived from even and odd-mode analysis. The formulas can take account of the arbitrary coupling of lumped ana/or distributed resonators. The advantage of this filter is its abilities to change freely the coupling structure between two resonators. Experimental bandpass filters for 2.4GHz Band are implemented and their performances are shown.