• 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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.9
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• pp.548-556
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• 2014

To cope with recently increasing demand for data traffics, heterogeneous networks have been actively studied, where small cells are deployed within a macro cell coverage with the same frequency band. To mitigate the interference from the macro cell to small cells, an enhanced Inter-cell Interference Coordination (eICIC) technique has been proposed, where ABS (Almost Blank Subframe) is used in time domain. However, there is a waste of resource since no data is transmitted in a macro-cell in ABS. In this paper, we propose a new interference management method by using a 3D sector beam based on Active Antenna System (AAS), where Genetic Algorithm (GA) is applied to reduce the antenna gain toward a small-cell. With the proposed scheme, the macro-cell and small cells can transmit data at the same time with the AAS antenna pattern generating reduced interference to small cells. The performance of the proposed scheme is evaluated by using an LTE-Advanced system level simulator.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.903-908
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• 2005

Existing ATC/ATO/TWC system has a ATC(Automatic Train Control) antenna for receiving the speed code, a ATO(Automatic Train Operation) antenna for obtaining the exact distance to go to platform and TWC(Train and Wayside Communication) antenna for communication between on-board and wayside system. This paper proposes the ATO/TWC antenna with tele-powering module, telegram transmitter/receiver module. This antenna communicates with a passive type tag(wayside Precision Stop Marker) for the information of distance from the stop position and a active type tag for the door command and status in the platform.

• Nuclear Engineering and Technology
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• v.54 no.10
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• pp.3614-3619
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• 2022

To operate the ion cyclotron resonance heating (ICRH) antennas in a better heating state and produce relatively low impurities, it is necessary to control the antenna spectrum by changing the antenna phasing. As the electrical length of the antenna feeding transmission lines is changing as a matter of the standing wave pattern at the ceramic supports, 90° elbows, T-connectors and antenna loops, we chose to measure the current at the grounding points of the antenna loops by antenna strap probe. The voltage drops along a small, several millimeter-long paths at the end of the antenna loops give a signal that is proportional to the current in the antenna loop. Through the simulation of the antenna strap probe and the actual measurement of the antenna phasing under vacuum conditions, the reliability of the antenna strap probe based diagnostic system have been successfully proved. Moreover, this system was successfully applied to the ICRH daily experiments in the spring of 2021. In the near future, the active real-time feedback control of the antenna phasing system will be developed based on this diagnostic system in the EAST tokamak.

• Smart Media Journal
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• v.9 no.4
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• pp.60-65
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• 2020

The monopulse tracking algorithm can estimate the location of a partner station based on an RF (Radio Frequency) signal. The location of the partner station is estimated based on the monopulse ratio curve (MR-C), which is calculated based on the sum and difference signal patterns of an antenna. Therefore, the range in which the estimated location can be calculated with high accuracy increases in proportion to the linear region of MR-C. In this paper, we proposed a method to extend the linear region of the MR-C curve using the beamforming technique for the tracking antenna system using the active phased array antenna. Simulation results based on the same antenna system, it was confirmed that the linear region of MR-C was enlarged by about twice as much as the general case where the proposed method was not applied.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.118-122
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• 2002

This paper is concerned with the design of the beam forming module that is a key unit of the active phased array antenna(APAA) system for mobile satellite communications. This module includes two blocks for main signal and tracking signal. Main signal block has the role of transmitting input signal from phased away antenna to tracking signal block. And, tracking signal block executes main roles, beam forming of tracking signal and electronic beam control. The several electrical performances of this module, phase characteristics and linear gain, etc., agreed with specifications needed for APAA, and for more clear verification of the performances, the satellite communication test of the APAA including the modules was accomplished in the outdoors.

• Journal of electromagnetic engineering and science
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• v.17 no.1
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• pp.14-19
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• 2017

In this paper, a planar directional beam-switchable antenna with four orthogonal beam directions is proposed. The proposed antenna is designed with two crossed active elements and two parasitic elements for each direction. The design methodology is described on the basis of the Yagi-Uda method for the active and parasitic elements, respectively. By adjusting the effective electric lengths of the parasitic elements, the roles of a director and a reflector are exchanged with each other. The planar four-way beam-switchable Yagi-Uda antenna is implemented. From the experimental results. The proposed design method is verified for orthogonal radiation beam switching.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.10
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• pp.1744-1751
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• 2006

In this paper shows the Designed and Manufactured active antenna for wireless LAN that is consisted of 5.5GHz band local LNA and Microstrip Patch Antenna. LNA improved noise special quality using NEC company's NE3210S01 and Micnstrip Patch Antenna designed to have omnidirectional characteristic. Designed $1{\times}2$ Microstrip Patch Antenna to have the gain of about 8.3[dBi], the input reflection loss -32[dB], VSWR showed 1.132, and the LNA gain 15[dB], input-output reflection loss was showed the characterstic of -20[dB].

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.6
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• pp.689-697
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• 2016

In this paper, we design and implement SPA (Switched Parasitic Antenna) antenna which can control its beampattern using multiple parasitic elements. By applying SPA antenna to wireless communication system and implementing beamforming scheme, we show that SPA antenna can be used to improve the performance of wireless communication systems. SPA antenna consists of a single active antenna and multiple parasitic elements around the active one, and can control its beampattern by switching the parasitic elements. Using this characteristic of the SPA antenna, it is possible to impelemtent beamforming technique with single RF chain, which enables to design low cost, low complexity and low power wireless communication systems. In order to verify the beamforming gain, we measure and analyze the system level performance, such as SNR, PER, and throughput.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.9
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• pp.1098-1106
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• 2007

This paper presents active antenna diplexers implemented into an ultra-wideband CPW(Coplanar Waveguide) fed monopole antennas. The proposed active antenna diplexer is designed to direct interconnect the output port of a wideband antenna to the input port of two active(HEMT) devices, where the impedance matching conditions of the proposed active integrated antenna are optimized by adjusting CPW(Coplanar Waveguide) feed line to be the length of 1/20 $\lambda_0$(@5.8 GHz) in planar type wideband antenna. The measured bandwidth of the active integrated antenna shows the range from 2.0 GHz to 3.1 GHz and from 5.25 GHz to 5.9 GHz. The measured peak gains are 17.0 dB at 2.4 GHz and 15.0 dB at 5.5 GHz.