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The module at the left displays a half-wave dipole of length l over 2 and width 2 a in the three dimensional coordinate plane along the z axis. A current I is flowing upward in the dipole. An array of length R is placed in the y z plane at an angle of theta from the z axis. The array R divides in the three components that are E sub R, H sub phi, and E sub theta. The component E sub R is acting in the increasing direction of the array R. The component H sub phi is increasing parallel to the x axis. The component E sub theta is pointing towards the y axis. The projection of the array R in the x z plane makes an angle phi from the x axis. The frequency of this antenna is equals 1.0 G Hz.

The module at the right plots a graph of a directivity of a linear antenna, as a function of its length. The horizontal axis of the graph shows the length of dipole lambda and the vertical axis shows directivity in linear units. The non-monotic curve passes through (0, 1.5), (0.5, 1.64), (1.25, 3.4), (1.5, 2), (2, 2.4), and so on. A point is highlighted at (0.5, 1.64).

The module displays the inputs at the bottom are as follows:

Set antenna parameters

Plot: directivity

Dipole length equals 0.5 lambda

Range

Maximum current equals 1.0 [ampere]

Range

Frequency equals 1.0 E 9 [hertz]

Range

Epsilon sub r equals 1.0

a equals 1.0 E-5 lambda

Data

Wavelength

Lambda equals 0.3 [meters]

Dipole length

L equals 0.5 lambda equals 0.15 [meters]

Directivity D equals 1.64092

Radiation impedance

R sub rad equals 73.1296 [ohm]

J X sub rad equals j 42.54791 [ohm]

Input impedance

R sub in equals 73.1296 [ohm]

J X sub in equals j 42.54791 [ohm]

Time-average total radiated power

Less than P sub tot greater than equals 36.5648 [Watts]