Antenna Apertures (Physical, Collecting, Effective, Scattering & Loss)
Types of Antenna Apertures
i) With different Antennas, different equivalent areas describe the power-capturing characteristics of an antenna.
ii) Different Apertures can be classified as per:
• Physical Aperture
• Collecting Aperture
• Effective Aperture
• Scattering Aperture
• Loss Aperture
Physical Aperture
• Physical Aperture explains the physical area of the antenna to capture EM waves.
• It depends on the physical structure of the antenna.
Collecting Aperture
• The collecting aperture of an antenna, refers to the effective area that is available for receiving EM waves.
• It considers not only the physical size of the antenna but also factors such as the antenna's gain pattern, efficiency, and any additional elements that might affect its ability to gather incoming signals.
• The collecting aperture accounts for the directional sensitivity of the antenna
Effective Aperture
When we receive power by antenna, it is always less than the basic calculations due to the following reasons:
• Horn is not uniform at opening.
• The electric field at the walls of the Horn antenna must be zero but practically not.
• Tapering Loss
• Conduction Loss
To understand these losses, we need to identify Aperture Efficiency.
Scattering Aperture
• From the Borders/Edges of the Antenna, there can be scattering of EM waves.
• These Borders/Edges of the Antenna belong to the Scattering Aperture.
Loss Aperture
Loss of EM waves may happen to different sections of the antenna
• Tapering Loss
• Conduction Loss
• Dielectric Loss
• Scattering Loss
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