Story: How we added the Array synthesis tool in Antenna Magus (part2)

I want to pick up the story on how we implemented the Array synthesis tool in Antenna Magus. The previous part1 of this blog series can be found here. In part1 I asked readers to look at the first prototype and to write down or comment on their first reactions.

This is what we learnt from the original usability tests:

  • The design confused people!
  • Fitting antenna parameters into the current Design Mode palette is a problem. Fitting array parameters into the palette would be impossible.
  • People don’t expect to be able to export a model of an array to a simulator. Most of the time, they are simply too big for full-wave analysis.

In the second design phase, we decided to go modal. The Array tool was separated from Magus’s Design Mode. One of the reasons for this was the sheer amount of information associated with arrays that had to be visible to the user. Another reason that emerged, after much discussion, was this: “Magus would not be taking mutual coupling into account.” By keeping the array calculator separate, we would not create that expectation. Parameters would be displayed in a large table in the main workspace, instead of trying to squeeze them in on the side-palette.

However, users would still start off by specifying an elemental pattern or dragging a pre-designed pattern of an antenna into the Array tool. After this, the excitation distribution and positions of elements, or some other objectives could be specified.

Array tool: Prototype 2 (click to enlarge)

Array tool: Prototype 2 (click to enlarge)

The prototype was drawn up in Balsamiq and five more users were tested.

This time, the usability tests went much more smoothly, however:

  • Users (as we expected) had trouble finding the array calculator
  • They seemed unwilling to start off with an element pattern
  • One tester began explaining the intricacies of measuring array S-parameter matrices to me and the difficulties of matching impedances. When I told him that this would not be taken into account by Magus, he said: “But this is useless!” It’s just a starting point!? Which is when he realised the intended value of the array calculator.
  • The design still felt a bit flaky, somehow.

Before designing the third prototype, we all sat around the table once again. Something was wrong, but I couldn’t quite put my finger on it.

In the 3d (last) part of this blog series, I will explain what final changes were made to the above prototype before we implemented the Array tool. Have a look at the above prototype so long (click to enlarge) and write down (or comment) what you think needed to change.

Author: Carien Fouch

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