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APPROACH TO NUMERICAL SOLUTION OF EM PROBLEMS 443

Figure 9.1.3a System-level specification example

Necessary steps may be represented as follows:

1. The parabolic antenna aperture efficiency factor k is defined by the expression (5.56) of
Chapter 5. Putting the given Ku-band wavelength ( = 300/ = 0.8491 in.), antenna gain
(D = 44.5dB = 28183), and reflector diameter ( = 72’’) we obtain k = 0.3971. Such

relatively low aperture efficiency offers a great deal of freedom in antenna elements’
selection.
2. The next critical parameter is the sidelobe level (SLL) we have discussed in Section 5.5.5
of Chapter 5. We have established that the SLL can be regulated by tapering or gradually
reducing the intensity of E-field from the center circular aperture to its edges. Referring to
the literature [1] we can find (Table 5.3 in Chapter 5) that the close to required SSL = -24.6
dB might be reached while E-field distribution is () = 1 − (2 ) and HPBW (Half
2
⁄
Power BeamWidth) is 73( ) [degrees].
⁄