Andrew77

I meant only the first 93.7 mm after the sma

Really I don't need, but I think balun can be some other thing like ferrite toroid on the feed cable after connector and 93.7 reduced to 60

They are three dipole right? Gain is ok, but lenght could be less: first 93mm can be less!? Should not change gain

Only 6.3dBi for a 300mm of antenna

This one in picture

@admin Do you have cst or stl file of the cilindrical metal collinear antenna ? Many thanks!

Not perfect but seems working!

Here is, for CST 2019 Happy new year from Andrea Double_BiFilar_Helix_Antenna_UHF_4_sheet_Brass.cst

Hi, further improvements for the matching: check this

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 mm

Yes, It Works! Have a nice day!

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

Gain VS frequency? Thanks!

Hello, I'm trying to design a NFC antenna @13.56 MHz for a reader, Antenna should have around 1,24 uH of inductance as simulation and calculation verified, but i'm not very sure about the set-up of CST (Frequency domain solver) I don't see Self-inductance up to 60 MHz I don't find The example given in the Examples of CST: "RFID Reader-Coil, 13.56 MHz CST example" could someone upload? (CST 2019) Many thanks NFC_13_56_MHz_V2.cst

I already posed a question about this antenna, I made some simulations, have you succeded to simulate it?

mmm interesting, but seems lumped port, I don't understand well... Do you have this example in .cst format?

Sure, The antenna is not matched.. Here is just to check the settings... CST_Article138_RFID Reader-Coil, 13.56 MHz.pdf

I past it again... Simulation are same as mine Did you use Transient solver? if not what mesh? Your bounding box how big is? NFC_13_56_MHz.cst

here is the original antenna: NFC_13_56_MHz.cst

Hi dear,how are you? I made antenna by myself, I understand that corners must be rounded but I started with this version to have a simpler meshing... The version with rounded corners gives me quite the same inductance (around 1.24 uH) I'm looking for the examples inside CST (13.56 mhz coil ) but I have a big db file for examples in CST directory so I don't kown how access Andrea

OOK thanks!

could you post the .cst file for this antenna? thanks

Seems that VSWR and gain go to the opposite direction!

,,,under simulation the real antenna... Dual_Band_Flower_Pot_2.cst

Ah! OK, I thought the spiral worked as a choke only... I will try