Single versus Multi- Mode Antennas
single mode: use for point sources
- one antenna, one detector
- absorbed power: P = kT
- effective area _2
multimode: use for distributed sources
- n-element antenna "array," n detectors
- P = nkT
- effective area n _2
- NEParray = ¦ n NEPsingle
regardless, D* __/ NEPsingle