The solar

radiation angle influences the generation of the reactive gas such as OH radical, and accordingly the concentrations of reaction products.

where [A.sub.r] is the receiving area of the photo detector, m = - ln2/ln (cos[[phi].sub.1/2]), d is the distance between the source and destination, [phi] is the

radiation angle, [T.sub.s]([psi]) is the gain of the optical filter sink, g([psi]) is the gain of an optical concentrator, c = 3 x[10.sup.8] m/s is the speed of light, [psi] is the receiving angle, FOV is the field angle of the source, M represents Lambert's radiation coefficient, and [[phi].sub.1/2] refers to the half power angle of the LED light source.

The measured and simulated results of

radiation angle and antenna gain are shown in Figure 6.

Nonetheless, electromagnetic analysis of the structure shows that the divergence of the beam increases as the

radiation angle gets closer to 90[degrees] with respect to the fiber's axis.

While the former corresponds to a loss due to the leakage of energy, the latter determines the

radiation angle of the main beam.

In Cha-bahar, Sun

radiation angle, one of the effective important factors in heat budget, is high, and it is even close to 90 degrees in some months.

Tuning of the maximum

radiation angle in a range of 40[degrees] was obtained.

It is shown that the measured maximum

radiation angle pointing toward the direction of [theta] = +13[degrees] and [theta] = -22[degrees], while the simulated result is [theta] = [+ or -]19[degrees].

where [psi] = 0[degrees] or 90[degrees] represents different observation planes, as well as [[theta]'.sub.mi] = arccos([absolute value of [C.sub.m][P'.sub.i]]/[absolute value of [C.sub.m][P.sub.i]]) is the

radiation angle, the point [P'.sub.i] is the projection of [P.sub.i] on the z-axis, [absolute value of [C.sub.m][P.sub.i] = r cos([[theta].sub.i]) - [z.sub.cm], [absolute value of [C.sub.m][P.sub.i]] = [square root of [absolute value of [C.sub.m][P'.sub.i] + [[absolute value of [p.sub.i]][P'.sub.i].sup.2]]] , and [absolute value of [P.sub.i][P'.sub.i]] = r sin([[theta].sub.i]).

Effects of

Radiation Angle (at a propagation distance of 180 mm)