• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.6
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• pp.919-930
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• 2001

This paper presents a wideband technique of impedance and axial-ratio bandwidth which uses the stacked planar array structure through optimum design of sub-polarization generating sections and parasitic patch. So, the effect of the dual-resonance characteristic can contribute to the bandwidth expansion of single fed planar array antenna using circular polarization which doesn\`t hire previous bandwidth expansion technique. The antenna can be used as a dual-band antenna by adjusting the resonance frequencies as well, and then the antenna is designed and fabricated in the frequency band of domestic satellite-TV service. This antenna has the performance of 9.7 % impedance bandwidth and 24 dBi of antenna gain. And it has also 2.8 % and 1.4 % of 3 dB Axial-ratio bandwidth at 11.4 GHz and 11.8 GHz respectively.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.397-400
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• 2005

In this paper, folded PIFA is proposed by using folding the end point of PIFA for the automobile DMB antenna. By turning down the end point on the opposite side of shortstrip, resonance frequency is presented at not $\lambda$/4 but $\lambda$/10. So the folded PIFA has size reduction effect approximately 60 % as compared to the conventional PIFA. Also by using the parasitic patch, folded PIFA provides wide band performance. As a result, the designed antenna can be in the application of Digital Multimedia Broadcasting(180 $\sim$ 210 MHz) antenna for the automobile.

• Tuberculosis and Respiratory Diseases
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• v.39 no.1
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• pp.103-108
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• 1992

Pulmonary paragonimiasis is the infectious disease of lung, due to 'Paragonimus westermani'. The clinical manifestations are various, and the main symptoms are chronic cough and persistent hemoptysis. Radiological findings mainly include thin walled cyst, migrating patch pulmonary infiltration, transient linear shadow, and hydropneumothorax, etc. The differential diagnosis should include pulmonary tuberculosis, pneumonia, other parasitic diseases, and rarely lung malignancy if the mass-like lesion is present. Recently, the incidence of paragonimiasis is very low. But the physicians should suspect paragonimus infection, if the patient has chronic respiratory symptom such as hemoptysis and lives in the endemic area such as Korea. A case of pulmonary paragonimiasis confirmed by histological basis of lung was presented with a review of the literature.

• Journal of Advanced Navigation Technology
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• v.22 no.4
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• pp.336-341
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• 2018

In this paper, we designed and implemented an ultra wideband (UWB) antenna with 5G mobile communication and WLAN bands rejection characteristics. The proposed antenna consists of a planar radiation patch with two slots, parasitic elements on both sides of the strip line and ground plane on back side. The upper n-type slot contributes for 5G mobile communication band (3.42~3.70 GHz) rejection and the lower n-type slot contributes for wireless local area network (WLAN) band (5.15~5.825 GHz) rejection. Parasitic elements were used in order to satisfy the voltage standing wave ratio (VSWR) less than or equal to 2.0 for UWB band (3.10~10.60 GHz) except two rejection bands. The Ansoft's high frequency structure simulator (HFSS) was used for antenna design and simulations. The simulated antenna showed dual rejection bands of 3.36~3.71 GHz and 5.13 ~ 5.92 GHz in UWB band, and measured result for the implemented antenna showed dual rejection bands of 3.40~3.72 GHz and 5.08~5.858 GHz. Simulated and measured VSWRs are less than or equal to 2.0 for all UWB band except dual rejection bands.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.1
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• pp.11-17
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• 2017

In this paper, an 8-direction switched beamforming antenna system at 28GHz frequency band is described for 5th generation wireless communication. This system is composed of an $8{\times}8$ Butler matrix and an 8-element patch array antenna. The antenna system switches beams in 8-direction in the wide range of ${\pm}40^{\circ}$. The antenna spacing is $0.65{\lambda}$ to achieve ${\pm}40^{\circ}$ steering range. Designed results show that the 8-direction beams are placed at ${\pm}6^{\circ}$, ${\pm}17^{\circ}$, ${\pm}28^{\circ}$, ${\pm}40^{\circ}$ offset from the center. Parasitic radiation effect from the large dimension Butler matrix need to be suppressed by employing a stripline structure.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1511_1512
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• 2009

This paper presents a polarization switching antenna integrated with silicon RF MEMS SPDT switches in the form of a package. A low-loss quartz substrate made of SoQ (silicon-on-quartz) bonding is used as a dielectric material of the patch antenna, as well as a packaging lid substrate of RF MEMS switches. The packaging/antenna substrate is bonded with the bottom substrate including feeding lines and RF MEMS switches by BCB adhesive bonding, and RF energy is transmitted from signal lines to antenna by slot coupling. Through this approach, fabrication complexity and degradation of RF performances of the antenna due to the parasitic effects, which are all caused from the packaging methods, can be reduced. This structure is expected to be used as a platform for reconfigurable antennas with RF MEMS tunable components. A linear polarization switching antenna operating at 19 GHz is manufactured based on the proposed method, and the fabrication process is carefully described. The s-parameters of the fabricated antenna at each state are measured to evaluate the antenna performance.

• Journal of Advanced Navigation Technology
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• v.4 no.1
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• pp.23-35
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• 2000

In this paper, the design for a PCS base station antenna which is using broadband method by a stacked structure has been studied. The sensitive parameters, such as the parasitic elements, the height of air layer between the upper and lower patch, and the variation of feed point, of the microstrip antenna that has stacked structure in a characteristics variation situation are classified and the characteristics has been investigated through the simulations. A designed antenna has following characters. Impedance bandwidth is Z57.5MHz(VSWR${\leq}$2), horizontal beamwidth is $64.1^{\circ}$, and gain is 14.7dBi. Therefore, it is confirmed the characteristics is good. In this paper, through the designing of a stacked microstrip antenna, we has investigated the availability for Korea PCS base station antenna.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.10
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• pp.1086-1095
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• 2008

In this paper, we designed and fabricated the trapezoidal antenna using the CPWG structure for Wibro and WLAN communications. This antenna has broadband characteristics using the basic trapezoidal antenna, and an H-shaped parasitic patch is making an expansion of resonance bandwidth and bringing stability of impedance matching. Especially, CPWG structure is combined two kinds of the structure which of a monopole antenna and a coplanar waveguide antenna. They make up for the weak point of the CPW which is variation of impedance matching according to varying the gap or size of the feed line and the ground. The designed antenna has occurred resonances of which the band of 2.2 GHz to 4.6 GHz(70.5 %) below the return loss of -10 dB($VSWR{\leq}2$) obtained in measurement, and it has an omnidirectional radiation pattern of H-plane. In addition, the changes of impedance matching appear slightly caused by the effects of the ground plane and the feed line.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.5
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• pp.435-443
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• 2009

In this paper, we propose a microstrip slot antenna that works in Bluetooth, Zigbee, WiMAX and WLAN frequency bands($2.4{\sim}5.825\;GHz$). To get the wide bandwidth from the microstrip antenna proposed, we insert a pair of parastic strips along the feed line on the FR-4 dielectric substance(${\varepsilon}_r=4.8$). Furthermore, a simple geometrical rotation with quadrilateral slot is designed to maximize the bandwidth and to gain a wider frequency band than the conventional rectangular slot antenna. A additional design of the loop type is added to a cactus-shaped patched for 2.4 GHz ISM frequency band. The total measured bandwidth of the antenna is from 2.4 GHz to 6 GHz and the maximum gains of the antenna are 3.82 dBi, 4.48 dBi, 6.41 dBi and 6.65 dBi at the frequencies of 2.4 GHz, 3.5 GHz, 5.25 GHz and 5.77 GHz.