• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.9
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• pp.46-51
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• 2013

In this paper, the optimum placement and shape of UHF antenna on the unmanned aerial vehicle (UAV) are analyzed by using the electromagnetic (EM) simulation on the various locations. The FEKO was used for the EM-simulation. In order to reduce the complexity of simulation and minimize the runtime and memory usage, the composite aircraft structure is simplified as the PEC model excluding the radome structure. The simulation was performed on the wing and ventral fin of UAV, and the antenna shape used the monopole, dipole, and bent monopole antennas. When the monopole antenna is mounted under the wing, two antennas need to be mounted under the right and left wings, and those antennas have to be switched as the direction of UAV wing to the line of sight (LOS) data-link (DL) ground antenna. In the case of mounting under the ventral fin, one antenna can be used regardless of the direction of UAV wing to the LOS DL ground antenna. Also, the antenna gain is improved by the blockage reduction. The antenna gain is further improved by using the bent monopole antenna. The optimum solution of UHF antenna placement and shape on UAV is to mount the bent monopole antenna under the ventral fin.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.1
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• pp.23-30
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• 2024

This paper dedcribes the design. verification, and analysis techniques for an advanced phased array antenna. When applying an active phased array antenna to an aircraft or missile, miniaturization of the array antenna and wide-angle beam steering characteristics can be unavoidable antenna design considerations. In particular, the active reflection coefficient characteristics when electronically steering a wide-angle beam is a design parameter that must be minimized in terms of system survival and system performance. As a radiator suitable for broadband characteristics and wide-angle beam steering, this paper designed an array structure using SFN and minimized the active reflection coefficient according to beam steering of up to 40° based on the spherical coordivate system angle. The bandwidth of the radiator was confirmed to be 3GHz based on active reflection in the Ka-band. In addition, the performance of the actually manufactured 8by8 array antenna wsa analyzed by measuring the single pattern of the radiator through a near-field test, mathematically synthesizing it, and predicting the Tx/TRx beam used in the seeker system.

• Journal of Satellite, Information and Communications
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• v.7 no.3
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• pp.105-109
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• 2012

In this paper, we developed an adoptable deployment method to the transmitting antennas of a ground based GPS system for aircraft. Aircraft generally uses satellite providing GPS signals for accurate position information, but transfers to ground based GPS signals time to time due to jamming signals or bad weather. The position accuracy of the ground based GPS system is highly dependent on the number and position of the GPS transmitting antennas. In this research, we found an algorism to predict the DOP due to the location of the GPS transmitting antennas and had an accurate DOP 2.5 area into 3-dimension from 0 to 10 km by 12 transmitting antennas.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.12 no.3
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• pp.1-12
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• 2004

When a straight-in landing from an instrument approach using ILS or VOR/DME is not possible or desirable because of topographical reason or bad weather, a circling approach maneuver is initiated by the pilot to align the aircraft with a runway for landing. Visual contact with the runway is necessary while conducting a circle to land maneuver. This research is to develop a new warning system based on a conventional marker system which alerts pilots to watch out for exceeding the circling approach area. The airborne system also uses the same receiver unit without any new installations. The objective of this research is to design and develop a Yagi antenna in a special form. The research includes computer simulations to determine the size of antenna radiation pattern and to compute an expected flight path in case of alarm to validate effectiveness of the system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.6
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• pp.1414-1418
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• 2013

In this paper, analyzed of UAVs operation altitude and range from the point of view of the data link. UAVs operation altitude is determined by the specification of the mission equipment and operational purposes. The link-of-sight analysis of data link equipment before deciding the unmanned aircraft operation altitude conditions should be considered. If GDT=0m installation then 32dBi antenna apply 15,779 meter is operation altitude. 44dBi antenna 7,927 meters. Operating altitude perspective, high-gain antenna is recommended of the long range communication.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.783-785
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• 2013

In this paper, analyzed of UAVs operation altitude and range from the point of view of the data link. UAVs operation altitude is determined by the specification of the mission equipment and operational purposes. The link-of-sight analysis of data link equipment before deciding the unmanned aircraft operation altitude conditions should be considered. If GDT=0m installation then 32dBi antenna apply 13,724 meter is operation altitude. 44dBi antenna 6,657 meters. Operating altitude perspective, high-gain antenna is recommended of the long range communication.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.252-252
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• 2006

• International Journal of Aeronautical and Space Sciences
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• v.10 no.2
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• pp.117-124
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• 2009

In the environment where various and complicated threat signals exist, RWR (Radar Warning Receiver), which can warn pilot of the existence of threats, has long been a necessary electronic warfare (EW) system to improve survivability of aircraft. The angle of arrival (AOA) information, the most reliable sorting parameter in the RWR, is measured by means of four-quadrant amplitude comparison direction finding (DF) technique. Each of four antennas (usually spiral antenna) of DF unit covers one of four quadrant zones, with 90 degrees apart with nearby antenna. According to the location of antenna installed in helicopter, RWR is subject to signal loss and interference by helicopter body and structures including tail bumper, rotor blade, and so on, causing a difficulty of detecting hostile emitters. In this paper, the performance degradation caused by signal interference by tail rotor blades has been estimated by measuring amplitude video signals into which RWR converts RF signals in case a part of antenna is screened by real tail rotor blade in anechoic chamber. The results show that corruption of pulse amplitude (PA) is main cause of DF error. We have proposed two algorithms for resolving the interference by tail rotor blades as below: First, expand the AOA group range for pulse grouping at the first signal analysis phase. Second, merge each of pulse trains with the other, that signal parameter except PRI and AOA is similar, after the first signal analysis phase. The presented method makes it possible to use RWR by reducing interference caused by blade screening in case antenna is screened by tail rotor blades.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.11
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• pp.982-989
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• 2013

Omni-directional antennas of UHF-Band are located on the top and bottom side of the Smart UAV in order to connect a link always. Therefore one of each antennas should be connected to a ground antenna. Because the communication link of the omni-directional antennas is influenced by the objectives around aircraft, the clearance of LOS(Line of Sight) should be achieved in order to avoid a loss of link. In this paper, the analysis results on the influence of the complex objectives placed around the antenna on the communication link are presented according to the change of attitude angles. The best positions of antennas are selected based on the electromagnetic analysis using XGTD tool which supports the modeling of antenna pattern. The flight tests of the Smart UAV were successfully performed with the selected antenna position.

• Journal of Advanced Navigation Technology
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• v.24 no.1
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• pp.1-8
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• 2020

In this research, we develop an airborne equipment radiating S/C-band signal to a target located at a long distance. RF interface of the equipment comprises band-specific transmitters and an broadband antenna to satisfy EIRP(effective isotropic radiated power) requirements. The equipment is in a shape of a POD like an aircraft fuel tank. The measured weight of the equipment is 119.8 kg, the CG(center of gravity) is 1391.35 mm and the MOI(moment of inertia) are 46.07 ± 0.05(I_yy) kg·㎡, 45.36 ± 0.09(I_zz) kg·㎡. All results are found to meet the requirements for aircraft installation. To verify flight safety, EMI(electromagnetic interference) tests (RE102, CE102), environmental tests (high/low temperature operation, altitude), intra-system EMC(electromagnetic compatibility) and HERP(hazards electromagnetic radiation personnel) tests have been conducted and all the test results met the requirements. It is confirmed that the equipment could be mounted on the aircraft by meeting all electrical and mechanical requirements.