Antennas Part 4

1
AntennasPart 4

• Coordinates
• Solid Angle
• Coordinate Review
• Analysis of Array

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Coordinates
3
Solid Angle
Each of these antenna appears as a point source
far from the array
4
Analysis of Array
I1Io ? a degrees I2Io ? 0 degrees
Note The Group Pattern (AF) is only for the
Electric Field. For Radiated Power, Farray
AF2
The total E-field pattern can Be found as shown
Unit Pattern is for E-field of Single element
5
Analysis of Array
This is the Antenna Factor for the E or H fields!

The power pattern is found using
6
Example

• For the 2 element array shown, sketch the
  normalized E-field and power pattern when the
  currents are (a) fed in phase, (b) fed 90o out
  of phase

AF 2cos(.5(Bd a)), Unit Pattern cos(?)
Enor cos(?)cos(.5(Bd a)),