• Title/Summary/Keyword: 지향성안테나

Search Result 204, Processing Time 0.031 seconds

SRDMAC Protocol Using Directional Antennas in Wireless Sensor Networks (무선 센서 네트워크에서 지향성 안테나를 이용한 SRDMAC 프로토콜)

  • Kim, Hae-Jung;Kim, Sang-Kyung;Kim, Chang-Hwa;Park, Chan-Jung
    • Proceedings of the Korea Information Processing Society Conference
    • /
    • 2008.05a
    • /
    • pp.893-896
    • /
    • 2008
  • 기존의 무선 센서 네트워크에서는 센서 노드는 하나의 전방향성 안테나와 하나의 무선 채널을 공유하여 데이터를 전송하므로 과다한 채널 경쟁과 센서 노드간의 데이터 충돌로 데이터 재전송이 자주 발생하여 불필요한 에너지의 소비가 많고, 소스 노드와 목적지 노드의 데이터 전송시 RTS(Request To Send)와 CTS(Clear To Send) 패킷을 사용하여 전파 전송 범위 전체에 대해 채널 예약을 하므로 공간의 활용도가 낮은 편이다. 본 논문에서는 전방향성 안테나의 문제점 및 단점을 보완하기 위한 방법으로 지향성 안테나를 사용하기 위한 SRDMAC(Spatial Reuse Directional MAC) 프로토콜을 제안한다. 제안된 프로토콜은 센서 노드 간의 데이터 전송시 충돌을 방지하여 데이터 재전송에 소모되는 에너지와 목적지 노드가 위치한 영역 일부분에만 데이터를 전송함으로 에너지 소모량을 줄일 수 있으며, 목적지 노드가 위치한 영역을 제외한 다른 영역의 이웃 노드와의 데이터 전송이 가능하므로 공간 재 사용율을 최대한 증가시킬 수 있다.

Frequency Characteristics of the Return Loss of a Broadband Double-Cone Antenna with Shorting Plate (단락판을 갖는 이중 원추형 광대역 안테나의 반사손실 특성)

  • Jang, Seung-Hoon;Hong, Deok-Gi;Kim, Hyo-gyun;Jung, Sung-Woo;Kim, Ki-Chai
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.27 no.2
    • /
    • pp.101-107
    • /
    • 2016
  • This paper presents the characteristics of a double-cone broadband antenna with compact and three-dimensional structure that can be used in UWB system. The theoretical analysis is conducted using a finite difference time domain(FDTD) method. The parameters are the radius, a height of broadband double-cone antennas with shorting plate, and the number of plates on a ground plane. This paper examines influence of structural parameters on return loss. The results show that a condition for an optimum structure of broadband double-cone antennas with shorting plate exists. It also shows that the broadband double-cone antennas with shorting plate have radiation patterns similar to those of a dipole antenna. To verify the theoretical analysis, computed results are compared to experimental results.

Broadband Hybrid Antenna with Directional Radiation Pattern Utilizing Epsilon Negative Zeroth-Order Resonance (ENG 영차 공진을 이용하여 대역폭이 개선되고 지향성 방사 패턴을 갖는 하이브리드 안테나)

  • Kim, In-Ho;Lee, Jeong-Hae
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.21 no.8
    • /
    • pp.886-892
    • /
    • 2010
  • In this paper, the hybrid antenna utilizing epsilon negative zeroth-order resonance(ENG ZOR) and $TM_{010}$-mode is presented. The antenna has a directional radiation pattern and improved bandwidth. To obtain a ENG ZOR and $TM_{010}$-mode, the hybrid antenna employs the mushroom structure and the microstrip patch, respectively. Two antennas of the mushroom and the patch are coupled by gap and fed by one coaxial feed. The frequencies of ENG ZOR and of $TM_{010}$ resonance are designed to be 4 GHz and 3.9 GHz, respectively. Because two resonant frequencies are set to be close, the dual-resonance can be formed, resulting in the broader bandwidth. Even though the radiation pattern of an ENG ZOR antenna is omnidirectional, the directional radiation of a microstrip patch antenna compensates the null of omnidirectional pattern of an ENG ZOR antenna. Thus, the hybrid antenna has a directional radiation pattern. The antennas having 4, 3, and 2 unit cells of mushroom structure are designed and analyzed. The antennas have fractional bandwidths of 4.29~4.95 %, gains of 3.16~5.57 dBi, and radiation efficiencies of 62.4~94.2 %.

Design of a Nature-inspired Wideband Sprout-leaf Antenna (자연모사 기반 광대역 새싹 안테나 설계)

  • Woo, Dongsik;Bae, Sunghyun
    • Journal of IKEEE
    • /
    • v.24 no.2
    • /
    • pp.536-542
    • /
    • 2020
  • This paper presents a nature-inspired wideband sprout-leaf shaped antenna with end-fire radiation pattern. A sprout-leaf shape angled-radiator was designed for wide beamwidth radiation patterns for motion detection sensors. An extended and truncated ground plane was used as a reflector for end-fire radiation patterns. To feed the balanced radiator, a broadband microstrip (MS) to coplanar stripline (CPS) balun was utilized with excellent amplitude and phase balance. The proposed antenna demonstrates wide frequency bandwidth from 8.5 to 14.5 GHz with wide beamwidth and the radiation efficiency of 90%. The measured gain is from 4 to 5 dBi and front-to-back ratio was 10 to 20 dB. It has been shown that the proposed antenna can be used for imaging sensors, phased array systems, and radars that require a wide bandwidth and a directional radiation pattern.

전자계이론에 대한 안테나 전파연구의 동향 기타

  • 박정기
    • 전기의세계
    • /
    • v.24 no.2
    • /
    • pp.22-24
    • /
    • 1975
  • 안테나, 전파전파에 관한 학회에서의 발표논문중 전체의 약 반수가 안테나에 직접 관계한 것이며 약 1/4이 전파전파에 관한 연구이고 나머지 약 1/4은 산란, 회절, 잡음, 기초이론, 수치계산이론등에 관한 것 및 전파응용에 관한 것으로 되고 있다. 또 안테나에 대한 연구논문중 가장 많은 것이 phased array 안테나에 관한 것으로서 대형레이더, 항공기용 레이다 등에의 응용 기타 다목적의 빔 안테나에 이용될 것을 전제로 연구되고 있다. 많은 안테나 소자를 어떻게 배열하여서 어떠한 진폭과 위상으로 급전하면 최량의 지항성 또는 바라는 지향성이 얻어지며 또 그 오차는 얼마가 되는가 등이 연구의 중심과제가 되고 있다. 참고로 1974년 미국 조지아 공과대학에서 개최된 안테나 전파국제학술회의에서 발표된 제목들을 알아보면 표1과 같으며 phased array 안테나가 기초적 검토 단계를 지나 실용화단계에 접어든 것을 직감할 수 있다.

  • PDF

Design of Omnidirectional Antennas Composed of the Parabolic Reflector (파라볼라 반사경으로 구성된 옴니안테나 설계)

  • 이동진;최학근
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.14 no.10
    • /
    • pp.1089-1095
    • /
    • 2003
  • In this paper, the 26 GHz band omnidirectional antenna that produces an isotropic radiation pattern in the azimuth plane and a directive radiation pattern in the elevation plane was designed by using reflector antennas. To investigate the reliability of the designed antenna, that was analyzed by using the aperture field method and the calculated value was compared with the measured value. An good agreement was achieved between the calculated characteristics and the experimental performance. We found that the designed antenna in this paper can be used as the omnidirectional antenna with reflectors and the analysis method in this paper can be used for the analysis of this type antenna.

3-bit Optical True Time Delay for 10 GHz Phased Array Antennas Composed of Optical 2$\times$2 MEMS Switches and Fiber Delay Lines (2$\times$2 MEMS 스위치와 광섬유지연선로를 이용한 10 GHz 위상배열 안테나용 3-bit 광학적 실시간 지연선로)

  • 이백송;신종덕;김부균
    • Proceedings of the Optical Society of Korea Conference
    • /
    • 2003.02a
    • /
    • pp.320-321
    • /
    • 2003
  • 위성통신 및 무선통신에서 안테나의 수신 감도를 향상시키기 위한 노력은 계속되어 왔다. 안테나의 지향성을 높이기 위하여 다수의 동형 단위 안테나들을 일정 방향으로 배열하여 안테나를 기계적으로 회전시키지 않고, 고정된 다수의 동형 단위 안테나들에서 방사되는 전파의 위상을 전자적으로 변화시켜 방사 빔을 주사하는 방법, 즉 위상배열 안테나(Phased Array Antenna)를 널리 사용하고 있다. 위상배열 안테나의 단위 안테나에서 방사되는 전파의 위상을 변화시키기 위해선 실시간 시간지연 시스템이 필요하다. (중략)

  • PDF

Study on Compensation Method of Anisotropic H-field Antenna (Loran H-field 안테나의 지향성 보상 기법 연구)

  • Park, Sul-Gee;Son, Pyo-Woong
    • Journal of Navigation and Port Research
    • /
    • v.43 no.3
    • /
    • pp.172-178
    • /
    • 2019
  • Although the needs for providing resilient PNT information are increasing, threats due to the intentional RFI or space weather change are challenging to resolve. eLoran, which is a terrestrial navigation system that use a high-power signal is considered as a best back-up navigation system. Depending on the user's environment in the eLoran system, the user may use one of E-field or H-field antennas. H-field antenna, which has no restriction on setting stable ground and is relatively resistant to noise of general electronic equipment, is composed of two loops, and shows anisotropic gain pattern due to the different measurement at the two loops. Therefore, the H-field antenna's phase estimation value of signal varies depending on its direction even at the static environment. The error due to the direction of the signal should be eliminated if the user want to estimate the own position more precisely. In this paper, a method to compensate the error according to the geometric distribution between the H-field antenna and the transmitting station is proposed. A model was developed to compensate the directional error of H-field antenna based on the signal generated from the eLoran signal simulator. The model is then used to the survey measurement performed in the land area and verify its performance.

Investigation of Micro-vibration Isolation Performance of SMA Mesh Washer Isolator for Vibration Isolation of X-band Antenna (SMA 메쉬 와셔 진동 절연기를 적용한 X-band 안테나의 미소진동 절연성능 검토)

  • Jeon, Su-Hyeon;Kwon, Sung-Choel;Kim, Dae-Kwan;Oh, Hyun-Ung
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.42 no.11
    • /
    • pp.988-995
    • /
    • 2014
  • Two axis gimbal type X-band antenna system has been widely used to effectively transmit the real time image data from the observation satellite to the ground station. The micro-vibration generated by stepping motor actuation and imperfect intermeshed gear configuration of the antenna is one of the sources to degrade the image quality. To guarantee a high quality image of high resolution observation satellite, micro-vibration isolation of X-band antenna is required. In this paper, the X-band antenna vibration isolation system using pseudoelastic SMA(Shape Memory Alloy) mesh washer has been newly suggested. The basic characteristics of the SMA mesh washer isolator proposed in this study has been measured through static load tests and its effectiveness has been demonstrated by the micro-vibration isolation test of the X-band antenna.