• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.2
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• pp.70-77
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• 2003

In this paper, analysis and measurement on coaxial connecter designed for packaging of microwave and micro strip transition structure are carried out. Even though researches on optimization of various kinds of transition structures have been conducted actively; however, the range of the application was very limited since they have been focused mainly on improvement of specific transmission line. Therefore, in this paper, we tried to analyze three kinds of substrates of which dielectric constants are 2,5,10 and are commercially used nowadays. Besides, we have confirmed reliability of FEM analysis, extracted equivalent circuit of transition area, found out factors determining extracted physical values, and made proof of electromagnetic variations for optimum characteristics. In addition, transition structure showing optimized characteristics on the basis of dielectric and microstrip structure was proposed. We reckon that the result of this research will apply with effect to transition design in microwave packaging development.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.3
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• pp.296-302
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• 2009

In this paper, a planar microstrip patch antenna is proposed using the slit on the top layer of a multi-layered structure for GPS application. The proposed antenna has a circular polarization at 1,575.42 MHz. This proposed antenna is fabricated on multi-layered FR4 substrate. The slits embedded on the top plane may yield to lower a resonance frequency and sustain a broad bandwidth. The proposed antenna size is $20{\times}20{\times}4.0\;mm^3$. The measured gain of 0.5 dBi, 10 dB bandwidth(VSWR 2:1) of 70 MHz(4.4 %), and 3 dB axial-ratio bandwidth of 15 MHz(1 %) have been obtained, respectively.

• Journal of Advanced Navigation Technology
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• v.23 no.1
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• pp.69-76
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• 2019

In this paper, a design method for an enhanced-sensitivity microwave sensor based on microstrip defected ground structure was studied for the permittivity measurement of planar dielectric substrates. The proposed sensor was designed by modifying the ridge structure of an H-shaped aperture into the shape of a capacitor symbol. The sensitivity of the proposed sensor was compared with that of a conventional sensor based on a double-ring complementary split ring resonator(DR-CSRR). Two sensors were designed and fabricated on a 0.76-mm-thick RF-35 substrate so that the transmission coefficient would resonate at 1.5 GHz in the absence of the substrate under test. Five types of taconic substrates with a relative permittivity ranging from 2.17 to 10.2 were selected asthe substrate under test. Experiment results show that the sensitivity of the proposed sensor, which is measured by the shift in the resonant frequency of the transmission coefficient, is 1.31 to 1.62 times higher than that of the conventional DR-CSRR-based sensor.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.523-526
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• 2002

The crosstalk among coupled microstrip lines is the major limiting factors of signal qualities in the high-speed digital and communication equipment. In this paper, a three-dimensional finite difference time domain (FDTD) method is applied to analyze the crosstalk between the coupled microstrip lines. The proposed structures of the coupled microstrip lines are investigated to reduce the coupling in a simple way by modifying their ground plane with an optimum gap. The examples of these structures with the different sizes of the gaps on their ground plane are studied. These structures are considered as the four-port network to evaluate transmission efficiency, near- and far-end crosstalk. Gaussian pulse is excited to evaluate the frequency characteristics from dc to 30 ㎓. The transmission efficiency, near- and far-end crosstalk of each structure of the coupled microstrip lines are demonstrated. The numerical results of this study show that the majority of crosstalk is the far-end crosstalk. The usage of the optimum gap on the ground plane can reduce the far-end crosstalk of the coupled microstrip lines while the transmission efficiency is nearly equal.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.11
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• pp.1164-1171
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• 2014

Bulk Current Injection(BCI) test is a method of injecting current into Integrated Circuit(IC) using a current injection probe to qualify the standards of Electromagnetic Compatibility(EMC). This paper, we propose a microstrip coupler structure that can replace the BCI current injection probe that is used to inject a RF noise in standard IEC 62132-part 3 documented by International Electrotechnical Commission. Conventional high cost BCI probe has mostly been used in testing automotive ICs that use high supply voltage. We propose a compact microstrip coupler which is suitable for immunity testing of low power ICs. We tested its validity to replace the BCI injection probe from 100 MHz to 1,000 MHz. We compared the power[dBm] that is needed to generate the same level of noise between current injection probe and microstrip coupler by sweeping the frequency. Results show that microstrip coupler can inject the same level of noise into ICs for immunity test with less power.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.10 s.89
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• pp.922-930
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• 2004

In this paper, the 3-dimensional microstrip antenna, where the lis is attached near the patch, on the pound and both patch and ground in zigzag, is designed and fabricated to miniaturize size of antenna. The path of surface current and permittivity in patch are increased because of attached Iris near the patch, on the pound and patch and found. In particula., the maximum size reduction effect among the three-type of $79.1\%$(17 mm$\times$90 mm) was presented in zigzag-type compared with the rectangular microstrip patch antenna(MPA) with a height of 9 mm at the resonant frequency of 1.575 GHz. The gain showed -1.15 dBd, -10 dB bandwidth showed 6.2$\%$(98 MHz), and HPBW of E-plane showed $154^{\circ}$. As that result we could confirm that the 3-dimensional structure with attached Irises is the proper form for the miniaturization of microstrip antenna.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.3
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• pp.305-316
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• 1998

The impedance matching network with the simplfied real frequency technique (SRFT) is proposed as a method for bandwidth enhancement of microstrip antenna. The validity of the technique is based on the relative frequency insensitivity of the radiation pattern and gain characteristics as compared to the resonant behaviour of the input impedance. The most significant feature of this technique is that there is no need to find any analytical description of the antenna and generator, and it only utilizes directly real frequency generator and load data over the prescribed frequency band. Furthermore, it is not necessary to invent an analytic form of the system transfer function to assume a matching network topology in advance. In this paper, the transmission line model is used to investigate the rectangular microstrip antenna, and based on the Fano's bandwidth-enlargement theory, the SRFT is introduced to design the matching networks of microstrip antennas in order to obtain a constant gain over the frequency band of interest. Two representative microstrip antnnas with different structure are fabricated and tested. From these procedures, it is obtained that the proposed impedance matching networks of microstrip antenna improve the impedance bandwidth nearly three times compared to the antenna without them.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.8
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• pp.921-926
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• 2014

In this paper, the characteristics of inset fed microstrip antenna loaded with CSLR(complementary single loop resonator) are studied. Effective permeability parameters of the SLR unit cell is retrieved from simulated scattering parameters, and structure parameters of the SLR unit cell are selected so that effective permeability is negative value at the operating frequency. The optimized inset fed microstrip antenna loaded with SLR for a $3{\times}3$ array in the ground plane of a conventional patch antenna is designed and simulation results of return loss and radiation pattern are shown. At resonant frequency 2.82 GHz, the overall dimension of the proposed antenna is reduced by approximately 56.8% compared to the conventional inset fed antenna. Simulation results are obtained by 3D FEM solver(Ansoft's HFSS).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.7 no.2
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• pp.139-146
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• 1996

In this paper, the total electric field antenna in the small loop and aperture plane structure to load a capacitance on transformed QMSA(Quarter-wavelength Microstrip Antenna) from MSA(Microstrip Antenna) is proposed, and the total electric field is shown that the calculated value is agreed resonably with experimental value. Itis a smalled antenna of the radiation element and ground plane with equal width. The designed and manufactured antenna can receive borth vertically and horizontally polarised waves to operating frequency of 1.5GHz; therefore this is available as a smalled antenna for wireless telephones and will be quit useful for indoor communication. Also, antenna's equivalent circuit with transmission line model is designed to find more accurate resonant frequency and is calculated return loss value. The calculated value is agreed resonably with experimental value.

• Progress in Superconductivity
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• v.2 no.1
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• pp.51-55
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• 2000

A $Y_1Ba_2Cu_3O_{7-\delta}$ square spiral microstrip antenna (YBCO antenna) was epitaxially grown on a $LaAlO_3$ substrate by laser ablation. Also fabricated was a gold square spiral microstrip antenna (gold antenna) having the same structure as that of the YBCO antenna in order to compare the properties of both antennas. Both the YBCO antenna and the gold antenna were operated in Ku (12-18 GHz) band, and their properties such as the return loss, SWR, power gain, and radiation patterns were investigated at 77 K. The return loss below -10 dB was obtained in two frequency ranges, i.e., 14.05-14.90 GHz, and 16-18 GHz for the YBCO antenna at 77 K (YBCO superconducting antenna), and in the frequency range of 15.05-17.60 GHz for the gold antenna at 77 K. The SWR bandwidths are 0.85 GHz and 2 GHz for the YBCO superconducting antenna, and 2.55 GHz for the gold antenna at 77 K. The gain improvement of the superconducting YBCO antenna over the gold antenna at 77 K was about 10 dB in the frequency range of 16 GHz to 18 GHz. The radiation patterns show the YBCO superconducting antenna has the omni-directional property of a spiral antenna.