CST Antenna Coupling

[Ukamurubasu 0]

Hi, 

I'm new to CST and antennas and I would like to evaluate the antenna to antenna coupling between two antennas on a satellite.

I have two quadrifilar helix antennas. Each antenna is fed with two discrete ports.

Do you know how to get the antenna to antenna coupling?

[clanon 258]

when you put TWO probes you'll get S11 for the interactions as S12 and S21  in the S-parameters results...

[Ukamurubasu 0]

Where do I put the probes?

[clanon 258]

discrete ports are the probes i'm talking about...coupling is directly calculated every time you use more than one port

[Ukamurubasu 0]

Yeah but one antenna has 2 discret port (1 and 2) and the other has 2 discrete ports (3 and 4).

 

I need the coupling between [1,0]+[2,90] and [3,0]+[3,90].

I hope I was clear

 

 

[Admin 2578]

Ukamurubasu,see this...

 

[Ukamurubasu 0]

Thanks Admin but I didn't find the answer i wanted.

I try to explain better: since my design is very large, I'm using field sources and when I use field sources I have the F-parameters.

I don't get them, are they like S-parameters? I just need to quantify the antenna to antenna coupling

[tomasbj 5]

@Ukamurubasu, active S-parameters or F-parameters in CST are useful for phased arrays, or antenna systems in which one would like to quantify the coupling effect between both antennas. This is useful if and only if you use simulataneous excitation. Otherwise there is no sense to look at this active S-parameters. These are measured when the device under test (DUT), such as an antenna, is in an active state, i.e., it is powered and possibly transmitting. In this state, the antenna or network can exhibit different characteristics due to the influence of active elements like amplifiers or transistors. Active S-parameters are crucial for understanding the performance of the device under real-world operating conditions. They can provide insights into parameters like active input and output impedance, gain under active conditions, and the stability of the device when transmitting. This is very important in phased arrays, beamforming. The conventional S-parameters we use to work are called passive S-parameters. You get it!

Added to this, calculate the reactive near field at the corresponding working frequency and check their separation distance on your satellite. So that if they are inside of the near field sphere, avoid it!. Because mutual coupling will be there.