Elements of Microwave link

Elements of MW link:

IDU Functions:
-Multiplexing /Demulteplexing of Tributaries
-Modulation/Demodulation with the Carrier
-IF conversion

IDU Block Diagram:

ODU Functions:

-Works as a up converter in TX direction and down converter in RX direction 
-TX/RX separation/combination with Duplexer
-Determines the Frequency of operation

 ODU Block Diagram:

Antenna Functions:
Works as an amplifier to overcome the fade margin and give desired AGC levels.

Wire carrying HF Current is surrounded by Electric and Magnetic Fields 

-Directive Gain
>Power Density radiated by antenna
>Power Density Radiated by Isotropic Antenna
  * Power Density measured at same distance
  * Both Antenna radiate the same total power






Antenna Specifications:
-Bandwidth:
  >Operating Frequency bands
  >Possible to tune antenna for slightly different frequency range while retaining the same characteristics
-VSWR: 
  >Is the Guaranteed peak Voltage Standing wave ratio within the operating band

-Gain: 
  >Stated in dBi (Decibels over an isotropic radiator). Primarily a function of antenna size.
-Front to back Ratio: 
  >In dB denotes highest radiation relative to main beam at 180+/-40 degree across the band.
-Half Power Beam Width: 
  >Nominal total width of the main beam at -3dB points
-Polarization: 
  >Can be single or dual polarized
-Isolation: 
  >For Dual polarized antennas. Refers to isolation between each polarized beam


Power Density:
-Radiated power Per Unit Area 
-Inversely proportional to the square of the distance from the source

ρ = Power density at distance r from an isotropic source
Pt= Transmitted power

Free Space Loss:
-Depends upon frequency of operation and distance between the Antennas

Loss= 32.4+ 20 log f + 20 log d

f = frequency of operation in MHz
d= Distance between the Antennas