• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.8A
• /
• pp.626-632
• /
• 2003

In this paper, forward-wave -3㏈ directional coupler with finite-thickness conductor and asymmetrical coupled lines are designed and experimentally verified using mode-matching based design methodology. Most of studies published in the literatures about the coupled lines are mainly concentrated on the adjustment of coupling amount by changing various geometric configurations. The analysis results in this paper show that thicker metalization requires reduced coupler length in the forward-wave directional coupler composed of asymmetrical coupled lines. Several forward-wave directional -3 ㏈ couplers with finite metalization thickness composed of asymmetrical coupled microstrip lines have been designed in the 5 ㎓ based on proposed design method. The measured data show -4.05㏈∼-4.09㏈ coupling at center frequency which is very closed to design value. The tight coupling has been implemented with accurate design methodology which take mentalization thickness into account.

• Proceedings of the KIEE Conference
• /
• 2001.07c
• /
• pp.1841-1843
• /
• 2001

Asymmetrical parallel coupled lines are used in a number of circuits such as multi-band coupler and combline type band pass filter. Although graphical results and formulas are available for the design of coupled lines, the design procedure is hard to use, because even- and odd- mode impedances are always expressed in terms of the physical geometry. In this paper, we introduce a method to find design parameter using finite element analysis. By employing the capacitance obtained by FE analysis, design parameters for each lines are extracted. To show the validity of extracted design parameter for asymmetrical parallel coupled line, we have designed and simulated a planar type combline band pass filter.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.1A
• /
• pp.77-83
• /
• 2004

Parallel coupled microstrip bandpass filter is widely used in microwave circuits. But this filter limits the filter applications because of the narrow bandwidth and the spurious passband at twice the basic passband frequency. In order to solve this problem, a method of the asymmetrical coupled microstrip lines on composite dielectric substrate is presented. Closed form method is used to analyze the asymmetrical coupled microstrip lines on composite dielectric substrate. An experimental filter is fabricated over $33\%$ bandwidth centered at 9GHz. Compared with the filter on a single substrate, this filter on composite substrate shows improvement of the spurious passband.

• Journal of electromagnetic engineering and science
• /
• v.14 no.2
• /
• pp.54-60
• /
• 2014

A systematic design for asymmetric coupled-section Marchand baluns is presented. Asymmetrically coupled transmission lines in multilayer configuration are exploited for constructing Marchand baluns. Design equations for characteristic impedance and electrical length of asymmetrical coupled transmission lines are derived for establishing a systematic design procedure. Novel Marchand balun based on these design equations is composed of two identical asymmetrical coupled transmission lines. However, contrary to the general conventional design approach where ranges for characteristic impedances of coupled lines are ambiguously capitalized, values for characteristic impedance and length are explicitly expressed. Our approach is fundamentally different from the design method using coupling coefficients where solution for coupling coefficient is inherently restricted. To verify the proposed method, one design example is performed for wideband Marchand balun in multilayer configuration, and is fabricated for verifying the design procedure proposed. Maintaining the return loss more than 10 dB, the bandwidth is measured from 0.43 to 1.0 GHz, where $S_{21}$ and $S_{31}$ show better than -4 dB. The measured phase and amplitude imbalances illustrate 0.5 dB and ${\pm}5^{\circ}$, respectively.

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 1986.10a
• /
• pp.110-113
• /
• 1986

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

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.18 no.4
• /
• pp.585-590
• /
• 1993

A wide passband filter consisting of 3-stage ssymmetrical coupler can be realized, where the admittance inverter parameters in equivalent circuit of asymmetrical coupled microstrip lines are given as a function of a fundamental design parameter of a bandpass filter. An experimental filter was designed over 22 percend bandwidth centered at 9GHz and optimized using Super-Compact. Measured forward transmission and forward reflection closely matched design data but measured insertion loss was slightly higher (0.7dB) than the designed value.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.18 no.11
• /
• pp.1663-1668
• /
• 1993

An X-band contiguous band diplexer is realized by using asymmetrical coupled microstrip lines. The design is based on the singly terminated low pass prototype filter and optimized by using SuperCompack. The designed channel 1 and channel 2 bandwidth is 22%, and 18% respectively, where the center frequency is 9,11 GHz. The measured results of the fabricated diplexer are in good agreement with the designed ones, but the measured insertion loss is slightly highier(0.5dB) than those of the designed value.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.13 no.6
• /
• pp.521-527
• /
• 2002

In this paper, we introduce a procedure to find design parameter for array coupled lines using 2-D finite element analysis. To extract design parameters using FE calculation, we set up several design conditions. In order to show the validity of our approach, we designed, simulated and fabricated a comb-line bandpass filter.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
• /
• v.4 no.3
• /
• pp.11-17
• /
• 1993

An active diplexer can be realized by using a MESFET and 2-sections of asymmetrical coupled bandpass filter, where the admittance inverter parameters in equivalent circuit of asym- metrical coupled microstrip lines are given as a function of an fundamental design parameter of a bandpass filter. An experimental active diplexer was designed over 22 and 18 percent bandwidth centered at 9 GHz and 11 GHz respectively, and the design data was optimized by Super-Compact. The gain performance was $6.2\pm0.3$dB in each band of 8.3~9.6 GHz and 10.3~11.8 GHz The measured bandwidth of the active diplexer was closely matched to design data but measured gain was slightly lower (1.5 dB) than the designed value.