Antennas are the ears and the megaphones of wireless systems. Understanding how to read antenna datasheets and how to best select antennas can be a dealbreaker for your wireless network. The figure summarizes some antenna basics. Takeaways:
- Antenna gain is measured in dBi with respect to an isotropic, perfect omni-directional antenna which comes with 0 dBi gain.
- MIMO is just an antenna configuration. Your radio channel defines what you can use it for (beamforming, spatial multiplexing, Rx/Tx diversity).
- Differences in antenna gain is measured in dB. A 20dBi antenna provides 10 dB higher gain than a 10 dBi antenna.
- A line of sight system can never achieve more than two orthogonal channels.
- Antennas don’t usually add any energy to your signal. It only directs energy. The conducted power plus the gain of the antennas impact both the range and the coverage area.
Understanding antennas, link budgets, interference, noise, propagation models (channels), radio sensitivity, radio protocols, traffic models and deployment scenarios are the keys to well-designed wireless networks.
