Want to Simulate Antenna Reception - quadrifilar helical - HFSS

[Fred_B]

Hi,

I am in the process of designing a quadrifilar helical antenna for the 70 cm band. I am using an old program called Antenna Model, which is good in many regards although falls short from my desire in two specific ways.

1) it fails to take into account distributed capacitance.

2) I would like to simulate the receive frequency response of the antenna. That is subject the antenna to a enviromental EM wave or stimulation and then measure the output at the terminals across a load.

I am familar with CST and HFSS and from my my own research it seems like only HFSS will do both of these things.

So, would anybody be able to point me in the proper direction as to how to set up HFSS to do this?

Best regards,

Fred B.

 

[SLK001]

Use the reciprocity property of an antenna and energyze the antenna's terminal. HFSS will then give you all the properties of the antenna from the EM wave impinging on the radiation boundary.

 

[Fred_B]

Use the reciprocity property of an antenna and energyze the antenna's terminal. HFSS will then give you all the properties of the antenna from the EM wave impinging on the radiation boundary.

When dealing with a antenna with a matching/phasing circuit what you propose fails to work.

I am working with QHAs which need a matching and phasing network between the geometry of the antenna elements and the feed line/port. With the match set for lowest reflection coefficient, meaning that the the lowest SWR will occur at the target frequency, the antenna may still have the a maximum transmission coefficient at a different frequency, with the difference depending on how far the geometry is off.

I have been simulating the antennas for best results, then proceeding to an anechoic chamber to test the transmission coefficient. This requires a lot of trial and err. adjusting the geometry then readjusting the matching circuit.

I would like to simulate the transmission coefficient analysis and subsequent adjustments, which are influenced by the distributed capacitance of the geometry of the elements and their enclosure, which I would also like the simulation to take into account.

 

[Fred_B]

Well, I guess I'll answer my own question.

FEKO will simulate antenna to antenna coupling. Set up one antenna with a source and then set up another with a load. Finally measure the power dissipated in the load.

Undoubtedly CST and HFSS can do this as well, although FEKO was on one so far that I could figure how to make it work due to FEKO's example files and accessible support.

 

[Fred_B]

Use the reciprocity property of an antenna and energyze the antenna's terminal. HFSS will then give you all the properties of the antenna from the EM wave impinging on the radiation boundary.

I managed to work this out in FEKO the long way, and after studying the results I realized I misinterpreted you response. FEKO's results show that the frequency of the peak power dissipated in the source of the transmit antenna is very close to the frequency of peak power dissipated in load of the receive antenna. So just doing as you suggest should be sufficient as a starting point before moving to a anechoic chamber.

 

[Chao Gu]

Hi Fred,

I am doing similar projects as you.
Could you please share your simulation model with me so I can verify my design? (gu.chao@msn.com)
Thanks so much.

Best regards,
Chao:smile: