Full version in "Microwave System Design Tools and EW Applications" published by Artech House, Inc.
Antenna Near Field Power
Two plot options are given, Power Density, or Power Received by an antenna of defined aperture. The powers are determined by dividing the transmitting and receiving antennas into sub-elements and integrating the powers between the elements. To achieve a reasonable accuracy many elements are used which can make this applet somewhat slow.
Default values may be modified and the display updated using scroll bars and the 'Enter' Button. The display automatically scales, dependent on the parameter values selected. The Fresnel Zone range is calculated from the common formula, 2xDxD/lambda; where D is the transmitting antenna largest (width) dimension.
The red curves indicate the power responses using the long-range inverse square law formula.
Mouse movement in Range - Power space indicates the main plot values relative to the mouse x-axis position.
The Save Button saves plot data to the Java Console ( slow if the console is open) with a summary of the relevant component parameters. Data may be selected on the Console using the mouse (Shift-click) and copied to the clipboard ( Ctrl C ) and saved in a text file for a permanent record or transferring to Excel for example.
If visual plots are required, Alt-Printscreen, copies the current window to MS Clipboard.
To speed up response in the power received mode, whilst testing the effects of parameter ranges, choose coarse plot resolution (C radio button).
Because of the relatively coarse integration, accuracy no better than 1dB can be expected.