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There are limits to this magic. While sparse arrays of antenna can get you very good angular resolution when receiving signals, they're not so magical for tran
by MichaelCollins 4y ago
There are limits to this magic. While sparse arrays of antenna can get you very good angular resolution when receiving signals, they're not so magical for transmission; as your array of transmitting antenna gets sparser, the power density of the beam also decreases proportionally. This is why aperture synthesis is great for radio astronomy, but next to worthless for far-field power transmission.
- amelius 4y agoWhy would the array get sparser? Isn't the point of an array to use more antennas, not fewer?
- ncmncm 4y agoYou can spread out a given collection of N antennas as wide as you like to get better angular resolution, but you lose signal strength at the target. Radio astronomers use big antennas and look for a long time. That doesn't work for communication. You can add more antennas, but those cost money. So, you use as many as you can afford, and space them out according to what you need. A too-broad antenna array on a satellite would have one set of problems, one on the ground others.