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Understanding Antenna Systems Within RF Communications

Infrastructure
Posted by James Donovan on 7 June 2017 Connect with James on LinkedIn Estimated reading time: 2 minutes

The antenna system is an important part of an RF communication system — without it, the system wouldn’t work. Of course as the antenna system is common to both the transmitter and the receiver; any change made in the antenna system affects both transmission and reception.

An antenna is formed of a few basic parts:

  • The Basic radiating element – which radiates energy in the required manner. An array of multiple elements is usually employed to increase directivity.
  • The Feed network – which transports energy from the input connector and distributes it to each radiating element with the correct amplitude and phase.
  • The Reflector – on sector antennas – which shapes the azimuth plane power distribution so that it radiates in only one spatial region. Also, this usually serves as a structural element.

The Housing or Radome – which provides protection of internal components from environmental factors like wind vibration, rain, snow and salt.

The antenna is the portion of the radio system found at the top of the tower. It could be a simple one-element antenna, or it could be a complex multi-element array. The antenna takes radio energy from the transmission line and radiates it into space; it also receives radio energy from space and feeds that received energy down the transmission line to the receiver. To oversimplify, an antenna is designed to radiate radio energy into space and collect radio energy from space.

 

The Efficiency of an Antenna

What is remarkable, though, is how efficiently this occurs. A two-way antenna is nearly 100 percent efficient. Of course, not quite all of the energy that is put in, is transmitted.

Factors affecting lost efficiency include a coaxial line that doesn’t perfectly “match” the input to the antenna, and power lost due to such things as “skin effect,” insulator dielectric, eddy currents, etc. But, since we can typically claim that an omnidirectional antenna radiates better than 95 percent of the watts it receives from the coaxial line (provided it “matches” the line) an antenna is an efficient device when compared to most other energy-emitting devices. Note that sector antennas are not quite as efficient but deliver benefits in other areas.

 

Antenna Theory and Passive Infrastructure

How these parts are designed together impacts the network coverage and capacity of wireless networks.

To put antenna theory into practice, get certified at the CommScope Infrastructure academy with the SP6910 and SP6920 online courses or browse our eBook here to better understand the passive infrastructure that underpins your network.