• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.135-138
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• 1998

This paper presents the results of measured permittivity of PCB sheet material in the frequency range of 0.1[GHz] - 2[GHz] and temperature range of $25[^{\circ}C]$ - $85[^{\circ}C]$. Microstrip lines with different physical length are implemented to measure the attenuation and phase shift of the signals though these lines. The loss factor of these materials could be obtained with the dielectric constant and the attenuation of the microstrip lines.

• 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).

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.2 s.344
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• pp.81-87
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• 2006

A small size broadband microstrip patch antenna with small ground plane has been fabricated using MEMS. Multiple layer substrates we used to realize small size and broadband characteristics. The microstrip patch is divided into 4 pieces and each patch is connected to each other using a metal microstrip line. The fabrication please process is simple and only one mask is needed. Two types of microtrip antennas are fabrication Type A is the microstrip antenna with metal lines and type B is the microstrip antenna without metal lines. The size of proposed microstip antenna is $8{\times}12{\times}2mm^3$ and the experimental results show that the antenna type A and type B have the bandwidth of 420MHz at 5.3 GHz and 480MHz at 5.66 GHz, respectively

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.427-431
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• 2007

Applications in present-day mobile communication systems particularly require miniaturized dimensions and low-profiles of antenna in order to meet the mobile units. Thus, size reductions and bandwidth enhancements are becoming crucial design considerations for practical applications of microstrip antennas. The motivation of further experiments have been stepped to follow those studies for achieving compact and broadband, even multiplied operation modes, which are greatly increased with much attentions recently. To obtain broadband, single-feed, circularly polarized characteristics of microstrip antennas, a design with feed-line ought to be a factor of two. Usually, diagonally balanced-line feeds with hybrid coupler are employed to attain circular polarizations. We firstly formulated DGS (Defected Ground Structures) based operation principles of the entire microstrip components and therefore were able to derive impedance variance of feed-lines. After verifying corresponding experimental results, we targeted the frequency bands of UHF RFID (Ultra High Frequency Radio Frequency IDentification) and approximately of 0.4-2.4GHz have exhibited remarkable two resonance amplitudes as a dual band antenna. Our secondary researches were aimed to design quad band microstrip antenna which represents four resonance characteristics within the identical frequency bands as well. Microstrip patch has been meandered to lengthen the electrical paths, and the other design criteria with respecting physical parameters including radiation patterns and impedance bandwidths measurements will be described for verification. Advisable applications of these antennas can be GSM850, GSM900, GPS (L1-1575 and L2-1227) and UMTS-2110 of cellular systems, which extremely desire multiband and minimum size.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.8 s.338
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• pp.41-46
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• 2005

Microstrip open-end and linear resonator are analyzed by method of moment (MoM) taking the entire-domain current distribution, found in literature, along the transverse direction of microstrip line. A transverse correlation function which incorporates permittivity, thickness and width of the line is derived. Numerical examples are investigated and compared with the available other data and methods in order to give the validity of the proposed method. It is found that the proposed method can generate more accurate results than the conventional methods.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.5
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• pp.238-242
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• 2001

In this paper, we extracted design parameters for re-entrant mode microstrip directional coupler using FE(finite element) calculations. The microstrip directional coupler suffers from a poor directivity due to effect of the inhomogeneous dielectric including both dielectric substrate and air in microstrip transmission lines. Thus, the phase velocity of even mode is not equal to that of odd mode. In order to improve the directivity of microstrip directional coupler, a novel re-entrant mode microstrip directional coupler was employed. In microstrip configuration, the high directivity can be reached by matching the even- and odd-mode effective phase velocities. Through the values of capacitance obtained from 2-dimensional FE calculations, the phase velocities for each mode and the design parameter were extracted for the proposed parallel coupled-line configuration. Based on the extracted design parameter with phase matching condition, we designed and fabricated a 30dB directional coupler at 0.85GHz. Experimental results show good performance with excellent, isolation and directivity.

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

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.11
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• pp.1090-1099
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• 2004

In this paper a novel design of equilateral-triangular microstrip antenna using PIN diode fur switching the resonant frequency is presented and experimentally studied. The proposed antenna has changed the resonant frequency by length of spur-lines on the patch, and PIN diodes are utilized to switch the spur-line on and off. The shape of the spur-line is changed according to the on and off states of PIN diode and the equilateral triangular microstrip antenna has different resonant frequencies in accordance with them. The resonant frequency is 1.22 GHz with off states since the surface currents flow the periphery of T shape spur-lines, while the resonant frequency is 1.82 GHz with on states since the surface currents are little effect with the conventional equilateral triangular microstrip antenna. The radiation pattern of the proposed antenna has a good linear polarization with the cross polarization of -20 dB both with on and off states.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.5
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• pp.1294-1303
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• 1996

In this paper, the microstrip anntenna with broad bandwidth is designed using parasitic element. In the designed cofiguration, parasitic element of the same resonating length but different width which is coupled to the nonradiating edge of a rectangular patch antenna. The driven element aloe is fed and the other part is operated as parasitic element. So the different patchs are resonating at differnt frequencies and this multiple resonance increase the bandwidth. The overall size of the antenna is not increased by adding parasitic element to a driven patch. Compared to the available wideband microstrip antennas, the designed antenna structure is bery compact. A theoretical explanation of the rectangular patch antenna coupled with prarsitic is analyzed by extending the theory of coupled microstrip lines. The theoretical and experimental results for a patch coupled with a single parasitic are presented.

• ETRI Journal
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• v.44 no.2
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• pp.260-273
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• 2022

This study presents a novel multilayer structure of parallel coupled-line bandpass filtercentered at 2.42 GHz with a fractional bandwidth value of approximately 19.4%. The designed filter can suppress harmonics with an appropriate frequency response by incorporating different techniques based on the multilayer technique. A combination of different techniques such as radial microstrip stubs and defected ground structure (DGS) and defected microstrip structure techniques are employed to suppress harmonics up to 5f₀. These techniques are used in two layers to suppress up to 5f₀. In addition, in this study, the effects of different parameters, such as the width of slot-line DGS, the angle of diagonal line slots in the upper layer, and the air gap between the two layers on the filter performance, are investigated. To verify the correct circuit operation, the designed filter is implemented and tested. The measurement results of the proposed filter are compared with the simulation results.