• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.5
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• pp.713-721
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• 2001

In this paper, parasitic patches gap-coupled microstrip antenna and stacked microstrip patch antenna combined with parallel coupled lines, which are a kind of wideband impedance matching network, are proposed to get the wider bandwidth. The iterative method using a distributed network is proposed to design the parallel coupled lines as a wideband impedance matching network. Measurements show that the proposed antennas provide wider bandwidths ~1.6 times and ~1.5 times those of conventional parasitic gap-coupled microstrip patch antenna and stacked microstrip patch antenna. In addition, measured radiation patterns show no serious variation of radiation patterns though the parallel coupled lines is added. The antenna gain is, however, lowered about 1 dB and 0.5 dB by the coupling loss in the parallel coupled lines.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.1 s.92
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• pp.78-83
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• 2005

LTCC filters have been widely used to wireless terminals. They generally adopt the multilayer structure. Some of multilayer LTCC filters are made of symmetrical parallel-coupled lines and anti-symmetrical parallel-coupled lines to reduce the length of resonators. The equivalent circuit of parallel-coupled lines was analyzed and applied to bandpass filters using multilayer parallel-coupled line resonators. The three-pole bandpass filter with the center frequency of 2.45 GHz is designed by using the proposed equivalent circuit and the measured results have good agreement with the design results.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1841-1843
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• 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
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• v.26 no.12B
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• pp.1724-1732
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• 2001

In this paper, a technique for increasing the bandwidth of microstrip array antennas using the parallel coupled lines on a single layer is presented. Four types of wideband microstrip array antenna are designed and the characteristics of each type are analyzed. In addition, an iterative method using a distributed network is proposed to design the parallel coupled lines as a wideband impedance matching network. Measurements show that the proposed antennas provide wider bandwidths ∼1.7 times those of conventional microstirp array antennas, while the sizes of proposed antennal are the same as that of a conventional array. And low cross-polarization level can be obtained through symmetrical locations of the parallel coupled lines section

• Journal of electromagnetic engineering and science
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• v.18 no.2
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• pp.73-77
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• 2018

This paper proposes a dual-band bandpass filter using stepped-impedance resonators (SIRs) with parallel coupled structures. The proposed filter adopts U-shaped SIRs with parallel coupled lines (PCLs) that have interdigital and comb-line shorted ends. The central PCLs build an upper passband and a transmission zero, and the two U-shaped SIRs build a lower passband. Four resonators and coupling structures are theoretically analyzed to derive its scattering parameters. A novel dual-band bandpass filter is designed and fabricated using the induced scattering characteristics. The measured results show that the fabricated dual-band bandpass filter has an insertion loss of less than 1.02 dB in the lower band of 2.45 GHz and of 3.01 dB in the upper band of 3.42 GHz, and a band-to-band isolation of more than 40 dB, from 3.14 to 3.2 GHz.

• 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.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.1
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• pp.94-100
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• 2002

In this paper, we proposed a 3 dB coupler using N-section parallel-coupled lines and designed a very compact one based on the analysis results. The coupled line has been analyzed by spectral domain method. After we obtain the s-parameters of N-section parallel-coupled lines by using port reduction method 4-port s-parameters are derived. The 3 dB couplers, which were fabricated, are not necessary to implement high impedance lines and tight coupling gaps as Lange Couplers because loose coupling is used. To realize a minimum section, we used the PCB that has high a dielectric constant and a thickness. The experimental results show that it has wide bandwidth of about 42 %(0.5 dB unbalance) from 3.6 GHz to 5.5 GHz and phase difference within 1 degree. Also, The isolation characteristics about 15 dB at its pass-band are obtained.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.7
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• pp.761-770
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• 2008

Impedance or admittance inverter is a conceptual 2-port device frequently used in microwave filter design. In this paper, the equivalent circuit using inverter for general loss less 2-port circuit is presented. Our equivalent circuit can be directly and easily represented with z- or y-parameters compared with the conventional methods. Based on the representation, the derived results for various coupled lines such as parallel coupled line and anti-parallel coupled lines are compared ours. In addition, the results of other workers for improvement of the distortion in frequency response of microstrip coupled line filter are derived using our representation and compared. The proposed equivalent circuit shows the difference with conventional equivalent circuit so the conventional design method can not be applied to parallel coupled line filter with our representation. So in this paper the novel design method is proposed and we showed the method yields more accurate design results.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2003.11a
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• pp.234-238
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• 2003

The LTCC bandpass filter using multilayer resonators is made of combline type and interdigital type parallel coupled-lines. The equivalent circuits of parallel coupled-lines are analysed. They are applied to make an equivalent circuit of LTCC bandpass filter using multilayer resonators. The 3-pole bandpass filter of the center frequency of 2.45GHz with 250Hz bandwidth is designed and fabricated. The simulated result of the bandpass filter are presented.

• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.313-316
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• 2003

The LTCC bandpass filter using multilayer resonators is made of combline type and interdigital type parallel coupled-lines. The equivalent circuits of parallel coupled-lines are analysed. They are applied to make an equivalent circuit of LTCC bandpass filter using multilayer resonators. The 3-pole bandpass filter of the center frequency of 2.45GHz with 200Hz bandwidth is designed and fabricated. The simulated result of the bandpass filter are presented.