You can expliot your 3D antenna model as impedance source file in CST design studio and check the matching performance at schmatic level in design studio.

On the other hand, you can also set a reactive impedance port in EM simulation by giving the values of L and C.

Dear Chaoyun Song ,

I have set the reactive impedance port in CST, but simulation error occur. I am trying to get this conjugate matching by using T match technique. When I placed The equivalent RC circuit in CST, Then occur mesh error. If you have any experience in RFID antenna design then kindly guide me .

If that is the case, you better use ADS to deal with this part (T/loop matching). CST can only handle a limited type of RC circuits. Your antenna impedance should be loaded to the ADS by using DAC (data access components. Please, check ADS help for more information on how to use it)

Dear Chaoyun Song

I am trying to resumulte this paper. kindly, see this paper may be I am making some mistake in the design. It will be your kindness.

Thanks

You can just locate exactly the point of 10+123j impedance on the Smith chart of your antenna. Then, use the conventional 50-Ohm port in your CST simulations and see how the change of your SRR element (i.e. the change of SRR layout) moves the complex impedance of your antenna closer or away from the 10+123j point on the Smith chart at the design frequency. In this way, you could be able to understand what SRR parameter is most important to provide the desired complex impedance of your RFID antenna.

Dear Andrey S. Andrenko ,

I am using T matching technique for impedance matching purpose.According to T match technique we can place its equivalent RC parallel circuit in the simulation. Which basically represents the chip. So, When I placed its discrete port in parallel with lumped element in CST, then only port placed in series with lumped element. Just tell me that how can I placed lumped element in parallel with discrete port in CST.

You need a 123 ohm inductor in series with your load. You can do this with a lumped component or network.

Dear Malcolm White ,

For impedance matching I am using T match technique. According to this technique we can used it equivalent RC parallel circuit in simulation. So, The chip which I am using is Alien Higgs 3 with complex impedence 25-j190. by following the datasheet its R and C values are 1500 ohm and 0.9pf. As it is clear that chip presents comlex impedence. So, Antenna for conjugate matching must have 25+j190 impedance. In simulation when I placed discrete port with 1500ohm and lumped element with 0.9pf then mesh error occour. I am using CST software for this simulation. Just tell me that how can we placed lumped element in parallel with discrete port.

Thanks

Sorry for the late answer - it stayed on my browser for a week and I just hit "add" today when I realised it hadn't gone. I hadn't seen the recent contributions.

The advantage of the method I've described is that you can run CST simulation of the actual tag antenna, and not using any RF circuit simulation. My understanding is you want to use SSR element in your RFID tag antenna in order to produce an inductive-type complex impedance to match it to the capacitance-type impedance of the chip. Is this correct? If so, you run CST MW simulation with the conventional 50-Ohm port excitation and optimize the parameters of SSR element to move the tag antenna impedance to 25+j190 Ohm point on the Smith chart.

Dear Andrey S. Andrenko ,

Yes, I am using SRR in RFID tag antenna in order to produce an inductive impedance which perfectly matched with the chip impedance. From your suggestion I understand that I move the port postion on SRR to locate the point on which SRR tag antenna provide 25+j190 impedance. Is I am correct? Further can we check impedance on smith chart in CST?

Thanks