天线原理介绍 Antenna Theory.ppt

* Mechanical Downtilt Pattern Analogy: Rotating a Disk Mechanical Tilt Causes: ? Beam Peak to Tilt Below Horizon ? Back Lobe to Tilt Above Horizon ? At ± 90° No Tilt * Mechanical Downtilt Coverage 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 8° 0° 10° 6° 4° Mechanical Tilt Elevation Pattern Azimuth Pattern * DB834H85RF-F0° Mechanical Downtilt 85° Quiz: What is the vertical beamwidth of a 4-element array? * DB834H85RF-F7° Mechanical Downtilt 93° * DB834H85RF-F15° Mechanical Downtilt 123° * DB834H85RF-F20° Mechanical Downtilt Horizontal3 dB Bandwidth Undefined * Electrical Downtilt Pattern Analogy: Forming a cone out of a disk Electrical Tilt Causes: ? Beam peak to tilt below horizon ? Back lobe to tilt below horizon ? At ± 90° to tilt below horizon ? All the pattern tilts “Cone” of the Beam Peak pattern * Electrical Downtilt Coverage 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 8° 0° 10° 6° 4° Electrical Tilt 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 Elevation Pattern Azimuth Pattern * Mechanical vs. Electrical Downtilt * VARI-TILT? With Variable Electrical Beamwidth (VEB), you can adjust anywhere in 30 seconds. * ASPD 9778° Electrical Downtilt * Remote Electrical Downtilt (RET)Optimization Local PC Local PC Local PC ATC200-LITE ATC100 Series ATC200 Series ATM Remote Locations Network Server ATMS ATMS ANMS * PCS A-Band Product Frequencies, Two-Signal IM FIM = nF1 ± mF2Example: F1 = 1945 MHz; F2 = 1930 MHz 1 1 Second 1F1 + 1F2 3875 1F1 – 1F2 15 2 1 Third 2F1 + 1F2 5820 *2F1 – 1F2 1960 1 2 Third 2F2 + 1F1 5805 *2F2 – 1F1 1915 2 2 Fourth 2F1 + 2F2 77