Modelling of Tx. antenna and Rx.antenna using HFSS

Hi Folks,

I will explain you my requirement and you pls guide me regarding it.

1. I have a RFID reader (Transmitting)antenna resonating at 865MHz. Whatever power that is being radiated, including the pathloss will be received by the Tag (Receiving) antenna resonating at 865MHz. This passive tag with the received power will in-turn power the chip.
2. I have taken dipole antennas at both ends for simplification purpose.
3. I want to check what is the incident power at the Tag and how much power will be given to the Tag chip?
4. I am going to use 4W EIRP for the transmitting antenna.

Now my queries:

1. How should I model the Tx. antenna, channel and Rx. antenna using HFSS?
2. How should I make the TX.antenna for 4W EIRP?
3. How should I measure the incident power at the Rx. antenna?

Is there any alternative way to model this and satisfy the requirement?

Please help me to solve the problem.

Salaam Shaik

To answer your question about EIRP of 4W, which is 36dBm. Gain of the antenna of dipole around 2dBi.so EIRP=power transmitted-losses+Gain of the antenna.so you have to set the source voltage in such a way that you have a 4W EIRP.

Hope that answers one of your questions

Regards
ChachitoEL

Yeah...I am aware of the fact. But I didn't get how to set a source voltage?

You can do that by HFSS--->Fields--->Edit sources and change the power to be solved accordingly

Regards
ChachitoEL

chachitoelflaquito said:

You can do that by HFSS--->Fields--->Edit sources and change the power to be solved accordingly

Regards
ChachitoEL

Click to expand...

Chachito,

I want to simulate antenna of EIRP 4w. When I simulate the design, and checked the antenna parameters in Radiation -> Infinite sphere -> Compute antenna parameters, I found the gain as 1.75. Depending on this gain, the power to be transmitted should be in the order of 2.29W. But when I do as in mentioned in your post, I am unable to change the power from 1W to the desired value. Is there any other way to do this?

Thanks!

---------- Post added at 07:28 ---------- Previous post was at 07:15 ----------

Chachito,

I was able to do it, by changing the scale factor. Sorry for bothering you.

Okay.

I hope you are progressing in your research,were you able to get EIRP of 4W

Regards

chachitoelflaquito said:

Okay.

I hope you are progressing in your research,were you able to get EIRP of 4W

Regards

Click to expand...

I am able to do so. But right now, I am struck at simulating the antenna with gain of 2dB instead of 6dB.
Any hint?

Seriously i would say check the gain because gain of a dipole is around 2dB.6 dB seems way too blown up for me.

Regards.

chachitoelflaquito said:

Seriously i would say check the gain because gain of a dipole is around 2dB.6 dB seems way too blown up for me.

Regards.

Click to expand...

Hi,

What does the "Peak Gain" represents which can be seen through Radiation -> Infinite sphere -> Compute antenna parameters.
The peak gain in attached file is 1.74. What does it mean?

According to FCC, EIRP is 4W. But the maximum power to be transmitted is 1W. So, the gain of the antenna is 4.
log 4 is 0.6 and when multiplied by 10, it is 6dB. So, I calculated in this way and thought of designing antenna with trasmit power of 1W and gain should be 6dB.

But I didn't understand the concept of "Peak gain".
Please clarify.


PS: Pls check the below lines copied from a url.

Transmitted power must be configured correctly to prevent potential interference problems due to the effective isotropic radiated power exceeding the limits as defined in FCC part 15.247(i).

As defined in FCC part 15.247(i), the power transmitted by the transmitter can only have a maximum power level of 1 watt or 30dBm.

The antenna can only have a maximum gain of 6dBi.

An antenna's maximum gain or peak gain is the gain in the main beam direction. figuratively you also have a gain in other directions as well but the direction of maximum radiation is peak gain.

"i dont understand what you mean EIRP is 4W,but the maximum power transmitted is 1W.so the gain of the antenna is 4."
4w is 36dBm. if your power is 1watt=30dBm minus the losses plus the gain should give you 36dB right.

Hope that helps
Regards
ChachitoEL

shaikss said:

Hi Folks,

I will explain you my requirement and you pls guide me regarding it.

1. I have a RFID reader (Transmitting)antenna resonating at 865MHz. Whatever power that is being radiated, including the pathloss will be received by the Tag (Receiving) antenna resonating at 865MHz. This passive tag with the received power will in-turn power the chip.
2. I have taken dipole antennas at both ends for simplification purpose.
3. I want to check what is the incident power at the Tag and how much power will be given to the Tag chip?
4. I am going to use 4W EIRP for the transmitting antenna.

Now my queries:

1. How should I model the Tx. antenna, channel and Rx. antenna using HFSS?
2. How should I make the TX.antenna for 4W EIRP?
3. How should I measure the incident power at the Rx. antenna?

Is there any alternative way to model this and satisfy the requirement?

Please help me to solve the problem.

Click to expand...

Did u get answer of your three questions? Can u pls share it all together becoz I am facing same question.

shaikss said:

Hi Folks,

I will explain you my requirement and you pls guide me regarding it.

1. I have a RFID reader (Transmitting)antenna resonating at 865MHz. Whatever power that is being radiated, including the pathloss will be received by the Tag (Receiving) antenna resonating at 865MHz. This passive tag with the received power will in-turn power the chip.
2. I have taken dipole antennas at both ends for simplification purpose.
3. I want to check what is the incident power at the Tag and how much power will be given to the Tag chip?
4. I am going to use 4W EIRP for the transmitting antenna.

Now my queries:

1. How should I model the Tx. antenna, channel and Rx. antenna using HFSS?
2. How should I make the TX.antenna for 4W EIRP?
3. How should I measure the incident power at the Rx. antenna?

Is there any alternative way to model this and satisfy the requirement?

Please help me to solve the problem.

Click to expand...

have you been gotten the answers of your questions. If yes would you please send it to me(kamal14_kuet@yahoo.com)