hello everyone
i hope you all be safe and sound during quarantine!
OK i designed an antenna (MPA) in CST. now i want to determine its equivalent circuit model by ADS. is it possible? and how should i do it? please share your knowledge about this with me (ASAP)!
with all respect, thanks!
Dear Maryam Darabi ,
In order to determine the equivalent circuit you have to obtain the input impedance of the antenna as a function of the frequency.
Physically you have a resonant antenna with the resonance frequency f0 equals that of the minimum S11 and a quality factor Q= f0/bandwidth.
Knowing the capacitance C of the patch you can get L as L= 1/w0^2 C.
As shunt resonance circuit one can get Rp= the parallel resistance = w0LQ.
One has also to ass the radiation resistance Rr= 2Prad/Vp,
Vp is the peak input voltage of the patch.
Bets wishes
thank you Mojtaba Joodaki , but would you explain more in details. i must import s parameter to ADS? how?
it would be a great help if you answer me. thanks.
Yes, one way could be to transfer the Touchstone file of your S-parameters into ADS.
thank you Mojtaba Joodaki . i did what you said. i transferred a touchstone file in ADS, but now i'm struggling with this : how to use it to get a circuit model from this s-parameter.
thanks again you really helped.
Now your problem is reduced to finding an equivalent circuit from S-parameters in ADS. Just use the ADS help for that or other examples in the internet.
hello Nasr Alkhafaji
, thank you for your explanation, it helped a lot, i'm on it! thanks.
Dear Maryam Darabi ,
In order to determine the equivalent circuit you have to obtain the input impedance of the antenna as a function of the frequency.
Physically you have a resonant antenna with the resonance frequency f0 equals that of the minimum S11 and a quality factor Q= f0/bandwidth.
Knowing the capacitance C of the patch you can get L as L= 1/w0^2 C.
As shunt resonance circuit one can get Rp= the parallel resistance = w0LQ.
One has also to ass the radiation resistance Rr= 2Prad/Vp,
Vp is the peak input voltage of the patch.
Bets wishes
thank you dear sir Abdelhalim abdelnaby Zekry for your explanations. i will work on it.
hello everyone
I did a lot of research and asked a lot of questions experts. after all I figure out that you can't get the equivalent circuit model of patch antenna automatically from ADS based on results in CST. so here what you should do:
1- design your antenna in CST
2- estimate circuit model of your design (we know a simple patch can be model as parallel RLC, you can use different papers to figure out how to estimate)
3- calculate RLC components with equations (if you search you will find relevant papers)
4- draw your circuit in ADS
5- use optimizer / tune tool in ADS. you can find ADS videos in YouTube.
check this paper:
Wireless Body Area Networks: UWB Wearable Textile Antenna for Telemedicine and Mobile Health Systems
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