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The module at the left plots a decreasing line for a large parabolic reflector of d greater than equal to 2 lambda. The horizontal axis of the graph displays T sub a from 0.0 to a, and the vertical axis of the graph displays antenna illumination from 0 to 1.

The module at the middle shows a graph. The horizontal axis of the graph represents z-axis while the vertical axis represents r sub a. The graph plots a curve along the vertical axis. The half part with length d over 2 of the curve lies above the horizontal axis while the other half part with length d over 2 lies below the horizontal axis. A small circle E sun theta in the fourth quadrant makes an angle theta with the z-axis. An arrow from the circle points towards the vertical axis. A text reads d equals 2.0 lambda. F equals 1.0 [gigahertz].

The module at the top right shows a graph. The horizontal axis represents theta in degrees ranging from negative 50 to 50 in increment of 50. The vertical axis represents d B ranging from negative 100.0 to 0.0 in increment of 25. The graph plots a curve that starts at (negative 50, negative 25.0), passes through (negative 25, negative 70.0), (0, 0.0), (24, negative 70.0), and ends at (50, negative 25.0).

The module at the bottom right shows a polar coordinate system. A curve is drawn in the left and along the vertical axis of the system, while three lobes are drawn in the right of the vertical axis.

The input is as follow:

Set antenna parameters

Illumination factor alpha equals 0.5

Antenna aperture d equals 2.0 lambda

Range

Frequency f equals 1.0 E 9 [hertz]

Range

Update

Elevation angle theta equals 45.0 [deg]

A radio button is on that reads the absolute value of E of theta or the absolute value of E of 0

A radio button is off that reads F of theta

A checkbox is checked that reads d B

Instructions

Data

Wavelength

Lambda equals 0.3 [meters]

Antenna aperture

D equals 2.0 lambda equals 0.6 [meters]

Theta equals 45.0 degrees

The absolute value of E of theta or the absolute value of E of 0

equals 0.003374263

F of theta equals the absolute value of E of theta squared or the absolute value of E of 0 squared

equals 0.00113857 equals negative 29.4364 d B

Directivity equals 37.26078

Beam width equals 31.51 degrees