#### Mahiou

##### Newbie level 3

I am a student doing Electronics, in my final year, my project is about designing an impedance matching circuit and a feed network for next gen communications systems

I am using the ADS suite, and I want to start with designing the impedance matching circuit

Now, i have a slight idea of what I am going to do:

My circuit needs to work with different frequencies. 3g, wifi, and 4g, and it has to match the impedance at these different frequencies using switches

The questions I cant find answers for are:

1. I realize the impedance of the antenna changes when the frequency changes. Is there a formula that relates the antenna's impedance to frequency ?

2. Are all the antenna modeled in the same way, i mean in terms of impedance and size, or is every antenna different?

I mean in my case, is there a standard antenna model that i will use, or do i need to speak with my supervisor and he picks a model for me ?

3. I would really appreciate it if someone showed me a link or a tutorial about how I can design a an impedance matching circuit in ADS.. I do understand the concept of the matching circuit. But i looked at ADS, and I cant find the components i am looking for

Like... for example. An antenna..

also, please, how do i simulate the antenna's impedance using ADS while changing frequency ?

I did look at google, and I looked at ads webpage. For a start I have no idea what i am loooking for because I never did Rf before

and second, the stuff i found is just not what I am looking for

Thank you for reading