• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.5
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• pp.87-92
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• 2022

In this paper, a study was conducted on the design of an array element that can be applied to the AESA radar for seeker. An antenna for application to AESA radar should choose an optimal radiation element to be applied to an array antenna in order to secure electronical beam steering characteristics, and consider beam steering characteristics when designing. In particular, in order to satisfy the wide-angle beam steering characteristics, the wide-angle impedance matching technique should be used to minimize the scan blindness region that may occur during wide-angle steering. As such, securing the stability of system operation is becoming an important design consideration for AESA radar. In this paper, WAIM is applied to the end of the radiation element to improve the characteristics of the radiation element applied to the AESA radar antenna device, and the change in the performance of the active reflection coefficient, which is a stable operation index of the system, is reviewed. The final performance result verified the validity of the proposed method by mathematically synthesizing the simulation data.

• Journal of Advanced Navigation Technology
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• v.28 no.2
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• pp.178-184
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• 2024

The radar installed on an aircraft has various operating modes depending on tactical purposes, allowing for the configuration of search areas according to each mode's operational objectives. active electronically scanned array (AESA) radar emits search beams sequentially according to a predefined search beam grid within the designated search area specified by the pilot to detect targets within it. It is crucial that the radar can stably search the area designated by the pilot for target detection, even as the aircraft's attitude changes. This paper focuses on stabilizing the search pattern in the air-to-air operational mode of aircraft-mounted radar to ensure stable target detection during roll and pitch maneuvers of the aircraft. The paper demonstrates its performance by simulating aircraft maneuvers and targets in a system integration laboratory (SIL) test environment.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.12
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• pp.1155-1164
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• 2011

In this paper, we proposed the transmit beam measurement method of active phased array antenna, which is installed in Korea's first developed naval medium range radar, using near-field measurement facility. The pulse-mode high power characteristics of active phased array antenna's trasmit-beam make it difficult to measure with general near-field measurement facilities where low power continuous RF signals are used. Thus, in this paper, the measurement method of active phased array antenna's transmit beam in conjunction with the near-field measurement facility, which is suitable for the high-power transmit beam measurement, and PNA-X network analyzer(Agilent Technologies), which can support pulse-mode measurement, was proposed and measured by near-field measurement techniques. And the EIRP(Effective Isotropic Radiated Power), the transmit characteristic of active phased array antenna, was measured by the near field measurement techniques and compared to numerical estimation which was nearly equal with small difference of 0.1 dB.

• Aerospace Engineering and Technology
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• v.11 no.2
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• pp.1-11
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• 2012

This paper describes the transmit/receive(T/R) module for the space based X-band active phased array radar. T/R module is the integrated module which is assembled by the transmitting and receiving RF semiconductor devices to enable the electronically beam steering of the phased array antenna and the key component of the SAR payload. T/R module can selectively receive the polarization signals by the switch according to the established technology but now the technological trend of the T/R module is to receive the horizontal and vertical polarization signal simultaneously. Therefore the research and development of the dual polarization receiving channel T/R module is actively in progress. In this study, as the prior research for the next generation SAR payload, the technological trend of the active phased array radar T/R module and the result of the preliminary design of the dual receiving channel T/R module were described.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.4
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• pp.514-522
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• 2000

In this thesis, a two-dimensional active phased array antenna without phase shifter is studied for two-dimensional beam scanning. A designed two-dimensional oscillator-type active array antenna, radiation elements and the oscillator circuits were combined with via-hole and coupled by slot on the opposite ground plane. The operating characteristics are analyzed and experimentally demonstrated , The two-dimensional $4\times4$ elements were designed for the proper coupling strengths and coupling phases by adjusting the width, length and offset position of slot-lines. The fabricated active phased array antenna shows the beam shift characteristics capable of scanning from $-17^{\circ}$ to $18^{\circ}$ with respect to broadside in one dimension, from $-5^{\circ}$ to $10^{\circ}$ in two dimension. The experimental results show that it is possible to use the oscillator-type active phased array antenna as a two-dimensional planar array antenna.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.6
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• pp.740-747
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• 2012

An Active Electronically Scanned Array(AESA) radar required necessarily as the Fire Control Radar(FCR) of recent fighters has ununiform detection range with regard to scan angle due to scan loss. Although the compensation method of scan loss in an AESA radar with variable dwell time is investigated, the effectiveness of the method in a fighter FCR with multi-function such as search, track, and missile guidance within limited resources should be considered systematically. In this paper, uniform search performance of an AESA radar using variable dwell time with regard to scan angle is derived. We assumed the search load of 50 % for case without changing dwell time in fixed frame time and showed the fighter FCR requirement for multi-function is not satisfied because the search load for the uniform search performance should be increased by about 100 %. On the other hand, in case of increasing the frame time for the uniform search performance and search load of 50 %, degradation of the search performance is shown by 86.7 % compared with the former. Based on these analyses, the effective beam operation strategy on an airborne AESA radar with uniform search performance in whole scan area is described with consideration of frame time, search load and performance as a whole.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.2
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• pp.172-182
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• 2014

In this paper, is is presented the result of design and fabrication for X band T/R module using in active array radar. The high power RF circuit was fabricated using GaN element, so that high power and high efficiency was fulfilled comparing with the previous T/R module that have under 50 W output power for X band. Designed X band T/R module demonstrated 200 W(53 dBm) peak power, 20 us pulse width with 0.4 dB pulse droop and 20 % duty cycle. And it has characteristics of 26 dB receive gain and 4.5 dB noise figure. The structure was applied to prevent serious damage of receive path and GaN HPA by transmitting power during trasmit time of a pulse radar.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.4
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• pp.281-290
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• 2021

For successful operations of an airborne Active Electronically-Scanned Array (AESA) radar, which has various advantages over traditional radar systems, accurate and robust navigation is critical. This paper discusses a study on the performance analysis of an integrated navigation based on the Embedded GPS/INS (EGI) system for an aircraft equipped with an AESA radar. The models for generating the inputs for the GPS/IMU are developed. A navigation filter for a loosely-coupled GPS/IMU system is constructed. Overall navigation performance assessment procedure using a six degree of freedom aircraft simulator - along with the GPS/IMU models and the navigation filter - is introduced. The steps of the performance analysis procedure are explained using a comprehensive case study.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.4
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• pp.414-423
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• 2015

Array error analysis and correction of active array antenna are described in this paper. Array elements composed of radiator and TR(Transmit & Recive) module have error(magnitude and phase difference among array elements) which affects SLL(Side Lobe Level). Error affectedness level depends on ideal SLL according to antenna aperture weighting, number of array elements and antenna effective aperture. To satisfy required SLL, correction of array elements is necessary; adopted differently per errors, and weighted differently per shapes of antenna and required SLL. Errors of every individual element had been defined, performance of the antenna with or without error correction had been estimated and proved through near field test.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.2
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• pp.168-173
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• 2008

In this paper, we have designed transmit/receive Module for X band which can be applied to active phase array radar system. AESA(active electrically beam steered array) is able to transmit high power as like TWTA with composition of TH Module and steer a main beam faster than mechanically steering system. The proposed structure of T/R Module for X band is brick type for physical structure, common leg structure electrically and small size design as MCM(multi chip module). The results show that the characteristic of proposed T/R module can fully cover the specification of required military radar application.