how to calculate the UHF tag's forward sensitivity by hfss or cst

[Louis666]

Hi, Sirs:

i am now simulate Alien's antenna 9662 with chip ucode 9  ,and when i read the datasheet of ucode9,so many impedance make me so confused。

we assemble the chip with single-slit, so the right impedance should be 10-j191? is that correct?

you can see the inlay in the attachment.

[EduardoZamora]

Hello @Louis666,

Hope you are doing well.

In case of single-slit antenna assembly, antenna shall be matched to that impedance (10-j191Ω).

Regards,
Eduardo.

[Louis666]

ok ,thankyou verymuch.

we simulate 9662 with HFSS,and we get the antenna's Gian and Impedance。

and by this formula

POTF = 𝐺 *𝑝 * (1 − |(Zchip-Zant∗)/(Zchip+Zant)|^2)/𝑃𝑡ℎ

𝑝 is the polarization mismatch factor（In most cases should be 1 ）,𝑃𝑡ℎ is the chip sensitivity,POTF is tag's forward sensitivity.

we calculate the UHF tag's forward sensitivity。however ,sometimes we find there may be inconsistencies between simulated values and measured values, and in many cases, the two may differ by 5-8dB，is that normal ？or the formula needs to be revised ?

[EduardoZamora]

Hi,

UCODE 9 has a self-adjust feature, which is an automatic mechanism that adjusts the chip sensitivity to a maximum in the operated environment for automated tag performance optimization. For more information, please refer to UCODE 9 Data Sheet, Section 9.6.2.

Regards,
Eduardo.

[Louis666]

Hi, EduardoZamora：

YES，we know that when test it's performance on tagformance，we disabled self-adjust feature before ,and we just compare the data after turning off self-tuning and simulation，they also can't match well.

Do you know what's the reason?

Maybe our calculation method is incorrect. How about you calculate the UHF tag's forward sensitivity ？can you provide how you calculate the tag's POTF？

thanks!

[EduardoZamora]

Hi,

My apologies, this information is not available. Some considerations for the sensitivity measurements are a 2.5 dBi gain antenna and center capacitor of self-adjust.

Regards,
Eduardo.

[Louis666]

Hi,EduardoZamora:

can you share something information to calculate the UHF tag's forward sensitivity by simulation？

THANKS!

[EduardoZamora]

Hi,

Our support is limited to the information that is available in the published documentation, and this information is not available.

I truly apologize for the inconvenience.

Regards,
Eduardo.

[Louis666]

sorry to forget add the attachment.