This article is a practical guide on how to feed a microstrip patch antenna on a finite ground using a waveguide source.
As an example, we will look at a microstrip circular patch antenna with a feed line connected by an SMA connector to a coaxial cable.
The front and side (section) view of the physical microstrip patch antenna for illustration purposes. Dimensions not to scale.
The circular patch antenna is modelled using a finite ground plane. Instead of using an approximation of the feeding mechanism (for example, a pin feed or edge feed), an SMA connector will be modelled as in the physical model. A waveguide port and waveguide source are added to the front face of the SMA connector to excite the patch antenna.
An example of a circular patch antenna on a finite substrate with a feed line at the bottom of the substrate in CADFEKO.
Left: 100% opacity; Right: 20% opacity.
To model the SMA connector:
- Import a model of an SMA connector and place it near the end of the feed line.
- Adjust the height of the pin to ensure that the pin makes contact with the feed line.
- To ensure electrical connectivity, union the patch antenna and the SMA connector.
Note: Confirm that the regions and faces of the connector have the correct material properties after the union operation.
A model of a SMA connector was imported as a .cfx file and placed near the end of the feed line. Opacity set to 20%.
To excite the microstrip antenna:
- Select the front face of the SMA connector.
The face of the SMA connector is selected.
- Add a waveguide port to the selected face.
A waveguide port is added to the selected face.
- Add a waveguide source to the waveguide port.
A waveguide source is added to the waveguide port.
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