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Types of antenna diversity compared

Short answer

Space diversity uses separated antennas, offering lowest correlation and highest gain but needs physical spacing. Polarization diversity uses co-located orthogonal polarizations, compact with slight gain reduction. Angle diversity employs directional beams, useful indoors. Space gives best performance; polarization is common at base stations due to compactness.

Discuss and compare different types of antenna diversity technique.

Antenna diversity uses more than one antenna to obtain independently faded copies of the signal. The main kinds are:

  1. Space diversity – identical antennas physically separated (≈ λ/2 at the mobile, 10λ or more at the base station) so fading is uncorrelated.
  2. Polarization diversity – two co-located antennas with orthogonal polarizations (V/H or ±45°); multipath scattering makes the two polarizations fade differently.
  3. Angle (pattern) diversity – directional antennas or beams pointing in different directions, receiving different groups of multipath waves.

Space diversity outputs are combined by selection, feedback, maximal ratio or equal gain combining.

FeatureSpacePolarizationAngle/pattern
BasisDifferent locationOrthogonal polarizationDifferent direction
Antenna sizeLarge (separation)Compact, one mastModerate
CorrelationLowestLow–moderateModerate
Diversity gainHighestSlightly lowerDepends on angular spread
BranchesAny numberUsually 2Several beams
Main useBS and mobileBS (cross-pol panels)Indoor, smart antennas

Summary: space diversity gives the best gain but needs room; polarization diversity gives most of the gain with a single compact antenna, so it is common on modern base stations.

✓ Answer checked by Claude Opus 5.5 (high effort)

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