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TheMaksimys

Bifilar Helix Antenna with Reflector

Hi everyone,

Photo1.jpg

I am attempting to make this antenna to work for ISM band (868-915 MHz). It seems that I am having troubles with the feeding structure, since the measured Return loss barely represents what I observe in simulations. The antenna is designed for the characteristic impedance of 200 ohms, so I am using the Mini-circuits 4to1 balun and connecting the balanced side rigth to the ends of helix, just as in the simulation. I cannot really find the reason for the discrepancy in the results, since even if I am feeding the antenna with unbalanced 50 Ohms it still demonstrates the return loss that is way off from the simulated results. I am attaching the simulation file and a few photos of the prototype. Thank you for everyone who will contribute to the discussion of this topic!

 

BFHA_tests_3.cst

Antenna_Model.png

Antenna_Simulated_Sparams.png

Photo3.jpg

Photo2.jpg

Antenna_Measured_Sparams.png

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,,,hi buddy...!!!

,,,you can try to do Clanon's impedance matching...

 

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1 hour ago, Admin said:

,,,hi buddy...!!!

,,,you can try to do Clanon's impedance matching...

 

Unfortunately not really an option, since I was looking for a wideband solution, but thank you for pointing me to this post!

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,,,,these would be the results on your Bifilar Helix Antenna....!!!

screenshot_39.png

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On 12/06/2024 at 9:04 PM, Admin said:

,,,,these would be the results on your Bifilar Helix Antenna....!!!

screenshot_39.png

Hi Dear, Please could you send me the *.stp file? Because I'm using CST2019, Many thanks! Andrea

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Yes, It Works!

 

Have a nice day!

 

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Have you tried to get the GND closer to the antenna? VSWR gets better! In this case GND plate moved to the antenna by 6 mmbifilar_2.jpg

bifilar_2_IRL.jpg

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