• ETRI Journal
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• v.27 no.3
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• pp.243-249
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• 2005

A mobile antenna for multimedia communications with Ku-band geostationary satellite KOREASAT-3 and JSAT-2A is presented. The forward link of the satellite communication is 11.7 to 12.75 GHz, and the return link is 14.0 to 14.5 GHz. The mobile antenna is designed to be a stair structure using 24 active phased array elements in order to provide a low profile, and to be at a non-periodic array distance using the genetic algorithm. Also, the designed antenna uses the double beam forming method for stable satellite tracking. The fabricated mobile antenna is examined using various experiments to confirm its capability for practical application. From the measured results, the fabricated mobile antenna system is confirmed to have a good performance.

• 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.

• 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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.8
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• pp.1963-1970
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• 1998

In this paper, a two-dimensional slotline coupling structure is proposed for the planar active phased array antenna system with scanning the beam by coupled oscillators without phase shifters. The operating characteristics are analyzed and experimentally demonstrated. The proposed two-dimensional slotline coupling structure consists of $|{=}|$-type slotline in the ground plane for the coupling of E-plane and H-plane. From the simulation results of coupling strength with the variation of width, length and the number of slotlines, the optimal coupling structure is proposed and applied to $2{\times}5$ elements of planear phased array antenna. The experimental results show that the beamwidth of E-plane and H-pland are $42^{\circ}$ and $15^{\circ}$, respectivly, and the scanning range is from $-20^{\circ}$ to $15^{\circ}$ from the broadside. Therefore, it is shown the two-dimensional slotline coupling structure for oscillator-type active phased array antenna can be applied to the planar phased array antenna system.

• 전자공학회논문지 IE
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• v.45 no.4
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• pp.54-59
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• 2008

In this paper, circularly polarized patch antenna with 2-stage LNA for the reception of S-DMB is presented. It used teflon didelectric substrate of ${\in}_r$=2.2 and the size is $40{\times}40{\times}15\;[mm]$. Experimental results of fabricated antenna show that bandwidths of input return loss and axial ratio are about 22 [MHz] and 25 [MHz]. Input return loss, output return loss, gain, and noise figure of the fabricated 2-stage LNA are $S_{11}$=-14 [dB], $S_{22}$=-18 [dB], $S_{21}$=26.8 [dB], and NF=1.14 [dB] respectively. The fabricated active type antenna has total gain of 30.4 [dB] at 2.642 [GHz].

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.12
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• pp.924-934
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• 2018

This paper describes the development and measurement results of C-band planar active phase array antenna for detecting and tracking radar(weapon-locating radar). The antenna is designed with 14 sub-arrays(12 main channels and 2 sidelobe blanking channels and approximately 3,000 elements of transmit-receive channel) to generate transmit and digital receive patterns. Using a near-field measurements facility, G/N, transmit patterns, and received patterns are measured. Receive patterns are implemented with digital beamforming by signal processing. The measurement results demonstrate that antenna design specifications were fulfilled.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.5
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• pp.103-108
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• 2023

In this paper, a performance enhancement study of an AESA antenna that can be applied to a seeker that serves as the eye of a missile was conducted, and the performance of the antenna was verified through actual measurement. When designing an AESA antenna, the optimization of the active reflection coefficient must be considered during transmission due to the mutual coupling between radiators that inevitably occurs, and the selection of a radiator that can overcome the space limitation of the seeker with a small size/light weight is an important design consideration. Accordingly, optimization in terms of electrical performance and low-profile structure is required through research on array antennas for application to the AESA structure. The radiator designed and measured in this paper was designed as an SFN that can satisfy the low-profile structure while enhancing the performance of a general vivaldi antenna. Through this paper, it was confirmed that SFN has the same broadband characteristics as general vivaldi antennas and has optimized characteristics required for AESA antennas. The structure optimized through simulation confirmed the pattern characteristics and active reflection coefficient characteristics through the fabrication of actual proto-type antennas.

• 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.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.6
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• pp.473-476
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• 2018

Herein, a $2{\times}2$ subarray antenna is designed to implement a VHF band active electronically scanned array. The Yagi-Uda antenna is used as a radiating element. The bandwidth enhancement and miniaturization of the Yagi-Uda antenna are achieved by optimizing the diameter of a driven element and the length of a director. In addition, the grid reflector is utilized to improve the front-to-back ratio(FBR) and to reduce both the wind resistance and overall system weight. The fabricated $2{\times}2$ subarray antenna fully covers the VHF target band($0.98{\sim}1.02f_c$). The measured maximum gain is 10.61 dBi and the FBR is larger than 26 dB.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.12
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• pp.95-110
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• 2012

The effect of a finite substrate size on the radiation characteristics of a two-element linear E-plane array antenna using microstrip patch antennas is investigated. The average active element pattern characteristics of two-element E-plane array antennas printed on different dielectric constant substrates with various substrate sizes and element spacings are analyzed. Using the average active element pattern, the radiation pattern characteristics of the array antenna versus scan angle is analyzed. The simulation results show that the diffracted fields of surface waves from substrate edges have a significant effect on the radiation characteristics of a 2-element E-plane array antenna. The distance between the center of patch antenna and the substrate edges on the E-plane for the enhancement of radiation characteristics of the array antenna is about $0.35{\lambda}_0$.