Yagi Antenna with Boom in FEKO

Hello everyone,

I've been able to model a simple yagi antenna using wires and wire feeds. Now I'd like to model a L-band yagi antenna in FEKO 5.4 including a metallic boom. The elements will be physically in contact with the boom (so I do need to tune the lengths).

Is it OK to use simple wire antennas, or would it be more accurate to use PEC cylinders?

If I use PEC cylinders, what type of port is best to use to feed the driven element directly? A wire port between the cylinder gaps?

Thanks for any guidance! I'm more familiar with HFSS than FEKO, but unfortunately the former is no longer at my disposal, so I'm trying to understand the FEKO interface better.

Are you sure that boom and Yagi elemnts are in electrical ontact?! In physical antennas they are seprated usually by dielectric.

Do you have more detailed description of the antenna?

Hello EMC,

My understanding of Yagi antennas is you can construct them in 3 ways:

1. Dielectric boom
2. Metal boom with elements insulated from the metal. The close proximity to the metal boom results in an electrical shortening of the elements, so this needs to be accounted for by adding sufficient length to the elements
3. Metal boom with elements electrically connected to the boom. Same situation as (2), but a larger "correction" may be needed.

I've seen Yagi's built these 3 ways, including (2) and (3). To be honest, it baffles me as to how (2) and (3) even work since I'd imagine that currents would flow in the boom and disrupt everything. I'll be doing some simulation in FEKO and take a look at the current distribution. Perhaps as long as the boom isn't resonant it works fine. Can anyone offer some physical insight to this?

Hello,

With wire antennas it will be Ok. However, the generator voltage should be distributed along wire segments, instead of using delta-gap approximations.