3.3. Directivity and Gain

Figure 3–4 shows a cross-hatched area dA in spherical coordinates that is bisected by the solid angle dW. Since dA = r2 sin q dq df = r2dW, the value of the cross-hatched solid angle in Fig. 3–4 is dW = sin q dq df. In general, however, solid angles can have other shapes. The solid angle of area A/r2 that subtends all of a sphere may be ... ................
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