• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.6
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• pp.1286-1291
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• 2013

Intensive researches on multiuser-based Massive MIMO are performed to increase the spectral efficiency. Although the Massive MIMO scheme based on huge number of antennas inevitably causes hardware and computational complexity in baseband and radio frequency (RF) elements, the problem can be mitigated without serious performance degradation by limiting the number of baseband and RF elements below the number of transmit antennas of base station and opportunistically selecting transmit antennas according to channel states. Accordingly, this paper proposes a simple antenna selection scheme for multiuser-based Massive MIMO systems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.7
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• pp.1558-1564
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• 2004

This paper shows the design of Active antenna which appled to 5.5GHz RF module for local wireless communication system. The LNA, which was designed Super low noise HJ FET of NE3210S01, is used to obtain a good noise figure characteristics. And the microstrip patch antenna was designed to obtain omnidirectional antenna characteristics. The measured LNA gain is 15 dB, input & output return loss is under -20 dB and VSWR under 1.5. The Single microstrip patch antenna input return loss is under -29 45, VSWR under 1.2.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.65-67
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• 2015

In this paper, small WLAN antenna was designed and investigated. Proposed antenna was configured for microstrip patch antenna ($29mm{\times}29mm$) that was mounted on RF4 dielectric substrate (relative permittivity 4.4, thick 1.6mm, tangent loss 0.025) with $45mm{\times}45mm$. In order to obtain a wide band characteristic, the cutting process was 3.2mm diagonal corners of the patch antenna located on the top of the substrate. Antenna feeding position for 50 ohm impedance matching was decided to be 5.1mm at the central axis in the horizontal direction. As a result, frequency bandwidth satisfying the condition of VSWR<2dB was 2.365-2.45GHz (85MHz, 3.53%) for considering WLAN.

• Journal of Advanced Navigation Technology
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• v.16 no.5
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• pp.766-772
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• 2012

In the present study, wideband microstrip monopole slot antennas which can be applied to the RF4CE Zigbee remote controller are designed. First I-shaped monopole slot antenna which has ${\lambda}g/4$ length at 2.45GHz is designed. In particular, a conducting via is used to connect the microstrip feed line and the ground plane surrounded with the etched slot for the bandwidth improvement. In order to reduce the antenna size, it is changed into L-shaped and T-shaped monopole slot antennas for which improve results of antenna performance are observed. In case of T-shaped monopole slot antenna, impedance bandwidth(VSWR<2) is about 3.32GHz, and also its radiation efficiency and gain is more than 90% and 2.1dBi respectively at whole operating frequency range. In particular, all of proposed monopole slot antennas have the end-fire radiations which has a maximum radiation power toward direction of open ends of monopole slots.

• Journal of IKEEE
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• v.16 no.4
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• pp.297-303
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• 2012

This paper proposes the effective design procedure for a broadband, double-ridged horn antenna for evaluating the performance of the RF energy harvesting system with a multi-band rectenna. Using multi-mode network analysis, the higher-mode scattering parameters of the transition and horn were acquired and applied to the antenna design, respectively. As a result, the computing time could be reduced and the calculated VSWR(voltage standing wave ratio) of the antenna was very similar to the analyzed result using fully electromagnetic simulation. And there was also good agreement between the simulated and measured results. The designed broadband antenna has a bandwidth of 660~6360 MHz and 6~13.7 dBi peak radiation gain.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.2
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• pp.143-152
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• 2019

In this paper, we described the design of Ka-band planar active phased array antenna which is applicable for small RADAR for airborne and seeker of guided missile. The antenna consists of about 1000 array radiating elements and is designed to be within 200mm diameter. We optimized the spacing of radiating elements to allow beem steering above ${\pm}55$ degrees of Field of view, and analyzed the performance of antenna. We confirmed that the Effective Isotropic Radiated Power (EIRP) of the antenna can be 94.22 dBm and receive G/T can be 1.68 dB/k through the designs of RF components and the verification of RF budget. The TX output of TR Module is designed to be over 1.3W for EIRP, and Receive noise figure of TR Module is designed to be less than 5dB for G/T.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.3
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• pp.329-335
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• 2008

This paper proposes a miniaturized half-circular-slot UWB antenna. Using an analysis of the neld patterns, we show that the original circular-slot UWB antenna operates on a series of multi-pole radiation based on $TE_n$ modes, and a perfect magnetic wall exists along an axis of symmetry on the antenna. Using the perfect magnetic wall we designed and fabricated the miniaturized UWB antenna on RF-60A substrate with t=0.64mm, ${\varepsilon}_r=6.15\;and\;tan\;{\delta}=0.0025$, which not only has the half size of the original but also maintains UWB characteristics. The measured gain of the miniaturized antenna is $-2.1{\sim}4.3dBi$, which is comparable with the gain, $-2.7{\sim}3.1dBi$, of the original circular-slot UWB antenna. The radiation pattern is also similar to that of the original antenna.

• Journal of Advanced Navigation Technology
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• v.13 no.3
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• pp.319-326
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• 2009

In this paper, the key technologies of Navigation receiver for GNSS sensor station are presented as a development result of a GNSS ground station in ETRI. A wide-band antenna and RF/IF components and SW signal processing unit to cover the GPS and Galileo signals for GNSS receiver are developed and its performance is verified by using GPS live signal and GNSS RF signal simulator from SpirentTM. We also gather GIOVE-A signal by using H/W antenna and RF/IF units in IF-level as sampling frequency and bit number, 112MHz and 8bits, respectively by using the developed wide-band antenna and RF/IF components. Data acquisition is done by using commercial data acquisition device from National Instrument TM. The gathered data is fed into SW receiver to process Galileo E1 to verify Galileo signal processing by Galileo live signal from GIOVE-A.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.1
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• pp.73-80
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• 2022

Sensors are applied to small aviation platforms for various purposes. Radio frequency (RF) antennas, which are representative sensors, are available in many forms but require the application of slot array RF antennas to ensure high performance and designation. Slot RF array antennas are applied to dip brazing techniques, but the yield and production time are determined by the proficiency of production personnel in a labor-intensive form. Unmanned aerial vehicles or drones, which are representative small aviation platforms, are continuously exposed to various random vibrations because propellers and multiple power sources are used in them. In this study, the fatigue life of slot array RF antennas applied with additive manufacturing was evaluated through the cumulative damage method (Miner's rule) in a vibration environment with a small aviation platform. For the evaluation, an S N curve obtained from a fatigue strength test was used.

• Journal of Advanced Navigation Technology
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• v.17 no.5
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• pp.491-496
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• 2013

In this paper, a half-wavelength folded-slot antenna, which can be applied to RF module for 3G mobile communications by which security lights are monitored and controlled, is proposed. The proposed antenna can be regarded as modified folded-slot structure which has the size reduced to a half of conventional ${\lambda}g$ folded-slot antenna and can be placed at the ground plane edge. In spite of that, the proposed antenna still maintain the advantage of conventional folded-slot antenna that input impedance is close to $50{\Omega}$. The antenna is designed and fabricated within the upper space of $40.5{\times}10mm^2$ on $40.5{\times}62mm^2$ substrate for 3G mobile communication frequency band. The measured impedance bandwidth and antenna gain are 390 MHz and 2 dBi respectively.