Processing math: 100%
  • Title/Summary/Keyword: active antenna array

Search Result 151, Processing Time 0.023 seconds

Development of High Voltage, High Efficiency DC-DC Power Module for Modern Shipboard Multi-Function AESA Radar Systems (함정용 다기능 AESA 레이더 시스템을 위한 고전압·고효율 DC-DC 전원모듈 개발)

  • Chong, Min-Kil;Lee, Won-Young;Kim, Sang-Keun;Kim, Su-Tae;Kwon, Simon
    • Journal of the Korea Institute of Military Science and Technology
    • /
    • v.24 no.1
    • /
    • pp.50-60
    • /
    • 2021
  • For conventional AESA radars, DC-DC power modules using 300 Vdc have low efficiency, high volume, heavy weight, and high price, which have problems in modularity with T/R module groups. In this paper, to improve these problems, we propose a distributed DC-DC power module with high-voltage 800 Vdc and high-efficiency Step-down Converter. In particular, power requirements for modern and future marine weapons systems and sensors are rapidly evolving into high-energy and high-voltage power systems. The power distribution of the next generation Navy AESA radar antenna is under development with 1000 Vdc. In this paper, the proposed highvoltage, high-efficiency DC-DC power modules increase space(size), weight, power and cooling(SWaP-C) margins, reduce integration costs/risk, and reduce maintenance costs. Reduced system weight and higher reliability are achieved in navy and ground AESA systems. In addition, the proposed architecture will be easier to scale with larger shipboard radars and applicable to other platforms.

Implementation and Verification of Channel Adaptive Private Broadcasting System Based on USRP (USRP기반 채널 적응형 개인방송시스템 구현 및 검증)

  • Yoo, Sinwoo;Oh, Hyukjun
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.26 no.5
    • /
    • pp.694-702
    • /
    • 2022
  • This paper shows a small and low-powered wireless communication system based on the ATSC broadcasting system using the ISM frequency band that can be used as a PBS(Personal Broadcasting System). It is designed to demonstrate a channel-adaptive CR(Cognitive Radio) system to provide a better service quality in the unlicensed band where co-channel interference exists. And it achieved very reliable communications by a closed-loop active phased array antenna. This ATSC-based personal broadcasting platform can be modified easily with given flexibility by using GNU Radio as an open-source signal processing platform based on USRP and implementing additional functions in FPGA. In addition, the chosen communication frequency resource can be managed and controlled by the return channel that transmits the channel status and communication parameters between transmission and reception in real-time.

Design of a 2-Port Frequency Mixer for Active Retrodirective Array Applications (역지향성 능동배열 안테나용 2-Port 주파수 혼합기의 설계)

  • Chun Joong-Chang;Kim Tae-Soo;Kim Hyun-Deok
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.9 no.2
    • /
    • pp.397-401
    • /
    • 2005
  • In this paper, we have developed a frequency mixer which can be used as a microwave phase conjugator in the retrodirective array antenna. The retrodirective array, which can reflect the incident wave retrodirertively back to the source direction without any priori information, requires phase conjugators to achieve the phase change of 180 degrees for the incoming signal. frequency mixers can efficiently serve as phase conjugators. The circuit topology is of the 2-port structure to avoid the complexity of LO and Rf signal combination and matching circuits, using a pseudomorphic HEU device. The operating frequencies are 4.0 CHz, 2.01 CHz, and 1.99 CHz for LO, RF, and If signals, respectively. Conversion loss is measured to be -ldB and 1-dB compression point -l5 dBm at the LO power of -10 dBm.

Design and Implementation of High Efficiency Transceiver Module for Active Phased Arrays System of IMT-Advanced (IMT-Advanced 능동위상배열 시스템용 고효율 송수신 모듈 설계 및 구현)

  • Lee, Suk-Hui;Jang, Hong-Ju
    • Journal of the Institute of Electronics and Information Engineers
    • /
    • v.51 no.7
    • /
    • pp.26-36
    • /
    • 2014
  • The needs of active phased arrays antenna system is getting more increased for IMT-Advanced system efficiency. The active phased array structure consists of lots of small transceivers and radiation elements to increase system efficiency. The minimized module of high efficiency transceiver is key for system implementation. The power amplifier of transmitter decides efficiency of base-station. In this paper, we design and implement minimized module of high efficiency transceiver for IMT-Advanced active phased array system. The temperature compensation circuit of transceiver reduces gain error and the analog pre-distorter of linearizer reduces implemented size. For minimal size and high efficiency, the implented power amplifier consist of GaN MMIC Doherty structure. The size of implemented module is 40mm×90mm×50mm and output power is 47.65 dBm at LTE band 7. The efficiency of power amplifier is 40.7% efficiency and ACLR compensation of linearizer is above 12dB at operating power level, 37dBm. The noise figure of transceiver is under 1.28 dB and amplitude error and phase error on 6 bit control is 0.38 dB and 2.77 degree respectively.

H Controller Design of Flexible Space Structure with the Uncertainty of Damping Ratio (감쇠비 불확실성을 고려한 유연구조물의 H 제어기 설계)

  • Chae, Jang-Su;Park, Tae-Won
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.26 no.4
    • /
    • pp.602-608
    • /
    • 2002
  • The flexible structure like solar array and antenna in spacecraft shows very sensitive responses to the inner or outer disturbance and noise. And the spacecraft becomes more complex and larger as it has various mission and role. But since the spacecraft need to have the limited mass, the thin and light material should be selected and this necessity induces the decrease d natural frequency and structural stiffness. It reduces the ability of adapting to the disturbance and induces the structural unstability. Certainly, the disturbance does not only make the structural unstability, but also give the bad effect to the precise attitude control. So it is necessary to control the vibration in the space. In this paper, the flexible structure control modeling with piezo sensor and piezo actuator is developed. The model uncertainty of damping ratio is overcome by robust control. The system equation is induced by the finite element method.

Efficient Implementation of FMCW Radar Signal Processing Parts Using Low Cost DSP (저가형 DSP를 사용하는 FMCW 레이더 신호처리부의 효율적 구현 방안)

  • Oh, Woojin
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.20 no.4
    • /
    • pp.707-714
    • /
    • 2016
  • Active driving safety systems for vehicle, such as the front collision avoidance, lane departure warning, and lane change assistance, have been popular to be adopted to the compact car. For improving performance and competitive cost, FMCW radar has been researched to adopt a phased array or a multi-beam antenna, and to integrate the front and the side radar. In this paper we propose several efficient methods to implement the signal processing module of FMCW radar system using low cost DSP. The pulse width modulation (PWM) based analog conversion, the approximation of time-eating functions, and the adoption of vector-based computation, etc, are proposed and implemented. The implemented signal processing board shows the real-time performance of 1.4ms pulse repetition interval (PRI) with 1024pt-FFT. In real road we verify the radar performance under real-time constraints of 10Hz update time.

Tunable Dielectric Properties and Curie Temperature with BST Thick Films (BST 후막의 가변 유전특성과 큐리온도에 관한 연구)

  • Kim In-Sung;Song Jae-Sung;Min Bok-Ki;Jeon So-Hyun
    • The Transactions of the Korean Institute of Electrical Engineers C
    • /
    • v.55 no.8
    • /
    • pp.392-398
    • /
    • 2006
  • The properties of tunable dielectric materials on RF frequency band are important high tunability and low loss for RF variable devices, variable capacitor, phased array antenna and other components application. Various composite of BST(barium strontium titanate) ratio combined with other non-electrical active oxide ceramics have been formulated for such uses. We present the tunable properties and Curie temperature on BST thick films. The grain growth of the weight ratio of BaTiO3 increased. This can be explained by the substitute Sr2+ ion for Ba2+ ion in the BaTiO3 system. The Curie temperature was shifted to lower temperature with increasing SrTiO3in the BaTiO3SrTiO3 system, because of decreasing the lattice constant. Also, the dielectric constant, tunability and K-factor of (BaxSr1x)TiO3 at over the Curie temperature decreased, at over the 60C fixation, maximum dielectric constant at Curie temperature and hence sharper phase transformation occurred at Curie temperature. The result were interpreted as a process of internal stress relaxation resulting form the increase of 90 domains induced the BST. As a result, It is concluded that over the Curie temperature, frequency response and DC field effect for the tunable properties of BST thick film are suppressed by the transition broadening. For the application of tunable devices, that the curie temperature was investigated to be increased.

X-band Compact Digital Phase Shifter Design (X 대역 소형 디지털 위상 천이기 설계)

  • 엄순영;전순익;육종관;박한규
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.13 no.9
    • /
    • pp.907-915
    • /
    • 2002
  • In this paper, a compact digital phase shifter to be used an active phased array antenna system for satellite communications was proposed. The even and odd mode analysis for a given reflection-type phase shifter, which uses a folded hybrid coupler as a base element, was performed and the design parameters were derived. Also, to verify experimentally the electrical performances of the proposed structure, X-band 4-bit digital phase shifter was designed and fabricated using Teflon soft substrate (εr;=2.17). Its circuit size was less than 3.5 cm × 3.0 cm, and it exhibited at least 50 % size reduction as compared with the conventional unfolded configuration. The experimental results of the fabricated phase shifter showed that the average insertion loss and insertion loss variation were less than 3.5 dB, ± 0.6 dB within the operating band, 7.9 ~ 8.4 GHz, respectively. And, input and output return loss were more than 10 dB, respectively. Also, the phase response of the phase shifter showed 4-bit operation with ±3 rms phase error.

Design of Ku-Band BiCMOS Low Noise Amplifier (Ku-대역 BiCMOS 저잡음 증폭기 설계)

  • Chang, Dong-Pil;Yom, In-Bok
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.22 no.2
    • /
    • pp.199-207
    • /
    • 2011
  • A Ku-band low noise amplifier has been designed and fabricated by using 0.25 um SiGe BiCMOS process. The developed Ku-band LNA RFIC which has been designed with hetero-junction bipolar transistor(HBT) in the BiCMOS process have noise figure about 2.0 dB and linear gain over 19 dB in the frequency range from 9 GHz to 14 GHz. Optimization technique for p-tap value and electro-magnetic(EM) simulation technique had been used to overcome the inaccuracy in the PDK provided from the foundry service company and to supply the insufficient inductor library. The finally fabricated low noise amplifier of two fabrication runs has been implemented with the size of 0.65mm×0.55mm. The pure amplifier circuit layout with the reduced size of 0.4mm×0.4mm without the input and output RF pads and DC bais pads has been incorporated as low noise amplication stages in the multi-function RFIC for the active phased array antenna of Ku-band satellite VSAT.

Design of Ground Clutter Prevention Fences for Radar Wind Profiler (연직바람 관측장비를 위한 지형 클러터 방지 펜스 설계)

  • WooJae Jung;JongChul Lee;JungIk Jeon;HyeongKi Lee
    • The Journal of The Korea Institute of Intelligent Transport Systems
    • /
    • v.21 no.6
    • /
    • pp.241-249
    • /
    • 2022
  • This paper discusses the design of a ground clutter prevention fence for a radar wind profiler (RWP). The design point of the clutter fence is to improve the quality of the received signal by removing the non-weather clutter coming from the side. In this paper, a clutter prevention fence composed of a metallash mesh around the RWP is proposed, and the phase center of the antenna, the length, and height of the down fence, and the height and slop of the top fence through M&S are designed. The designed ground clutter prevention fence and 256 active phase array antennas were used as basic data. The effectiveness of the design was confirmed by a simulation. The side lobe in the ±90° direction was reduced by more than 30dB depending on the presence or absence of the designed ground clutter prevention fence. The fence was manufactured by 3D modeling, and the clutter shielding performance of approximately 20dB or more on the side of the antenna (±90°) was confirmed by applying it to the currently operated RWP.