Helix Antenna Design with Antenna Magus and FEKO
Antenna designers often start with a standard design, but have to customize the design to achieve better than typical performance. In this work requirement Antenna Magus can assist by creating the initial CADFEKO antenna model of the standard design. In doing so, it provides detailed knowledge of how to model such an antenna optimally in FEKO, absolving antenna designers of the responsibility to know and understand the different FEKO modelling and solution methods. Antenna designers can then focus on customizing the antenna by simply modifying the CADFEKO geometry that was export from Antenna Magus.
The following example illustrates this workflow.
Design a helix antenna, maintaining gain bandwidth, but improving on VSWR and axial ratio bandwidth.
Use the Antenna Magus keyword search capability to find a helix antenna. Select the appropriate antenna in the filtered list and click on the "export mode" button in the task ribbon. Fill in the appropriate details for the basic helix model and export the FEKO model.
Now that the CADFEKO model has been created, it is a simple task to create non-standard variants of the model, e.g.
- Loft the edge of the ground plane to form a small metal cupped ground plane around the helix base. This operation requires only an edge selection and loft operation.
- Taper the top few turns of the helix to end in a smaller radius. This operation requires only the modification of the creation method for the top part of the helix.
- Use both the lofted base and tapered helix modifications.
|Edge loft model||Tapered end radius||Edge loft and tapered end radius|
Note that no modification was made to the port and source setup of the original model. This was left as exported by Antenna Magus! Running these models for a frequency sweep of 600 MHz to 1.4 GHz is now a simple matter. Comparing the results in POSTFEKO shows that:
- Far-field gain remains constant across the band of operation.
- Axial ratio of the tapered and loft & tapered models are better than for the standard helix model.
- VSWR of the tapered and loft & tapered models are better than for the standard helix model.
The design workflow, assisted in Antenna Magus, resulted in an exceptionally quick way to evaluate three options for non-standard modifications to a helix antenna.
|Far-field gain||Axial ratio||VSWR|