Antena天线设计资料.pptVIP

* 中国无线门户 Antena By Uke Kurniawan Usman Laboratoria SISKOM – STT Telkom uku@sttttelkom.ac.id 中国无线门户 Antenna - How it Works The antenna converts radio frequency electrical energy fed to it (via the transmission line) to an electromagnetic wave propagated into space. The physical size of the radiating element is proportional to the wavelength. The higher the frequency, the smaller the antenna size. Assuming that the operating frequency in both cases is the same, the antenna will perform identically in Transmit or Receive mode 中国无线门户 The type of system you are installing will help determine the type of antenna used. Generally speaking, there are two ‘types’ of antennae: Directional - this type of antenna has a narrow beamwidth; with the power being more directional, greater distances are usually achieved but area coverage is sacrificed - Yagi, Panel, Sector and Parabolic antennae - an EUM, NCL Station/Master will use this type of antenna in both Point to Point and Point to Multipoint 2. Omni-Directional - this type of antenna has a wide beamwidth and radiates 3600; with the power being more spread out, shorter distances are achieved but greater coverage attained - Omni antenna 中国无线门户 Macam – maca konfigurasi antena Dipole Dipole dengan pemantul Yagi Dipole dengan pemantul dan penyearah Horn Hpbw Parabola dengan prime focus Parabola dengan casegrain 中国无线门户 Yagi better suited for shorter links lower dBi gain; usually between 7 and 15 dBi 中国无线门户 Parabolic used in medium to long links gains of 18 to 28 dBi most common 中国无线门户 Sectoral directional in nature, but can be adjusted anywhere from 450 to 1800 typical gains vary from 10 to 19 dBi 中国无线门户 Omni used at the CCU or Master NCL for wide coverage typical gains of 3 to 10 dBi 中国无线门户 An antennas polarization is relative to the E-f