ABSTRACT

The radiation intensity is the power-per-unit solid angle in the direction and denoted by . The average radiation intensity over radi-

ans (solid angle) is the total power divided by . Hence, Eq. (10.1) can be written as

It follows that

As an approximation, it is customary to rewrite Eq. (10.3) as

GD G Ae

GD maximum radiation intensity average radiation intensity

--------------------------------------------------------------------------------=

θ φ,( ) P θ φ,( ) 4π 4π

GD 4π maximum radiated power unit solid angle⁄( )

total radiated power -------------------------------------------------------------------------------------------------------------------------------------=

GD 4π P θ φ,( )max

P θ φ,( ) θd φd

∫ ---------------------------------------=

where and are the antenna half-power (3-dB) beamwidths in either direction.