## Electronics

#### Question on Active Impedance and current measurement in an Antenna Array

• siva_puranam
Subscriber

Dear all,

I am simulating an array of dipoles using lumped elements that are normalized to 50 Ohms.

I want to ensure that I put in a specific amount of current, say 1A in all of them. I obtained the active impedance of each antenna in the array at the required frequency and then calculated the Power that needs to be input for each antenna by using 0.5* (1) * (Active Z + 50), where the 50 Ohm term stands for the port impedance.

I re-simulated the design and used the method outlined to calculate the current going through the antenna  ( basically this is Ampere's Law where you define a contour and integrate along the contour ) at the feed and this is not close to 1A of current that I expected.

Does not the Active Z take mutual coupling into effect ? I thought it did.

Could you guys let me know if I need to consider anything else or if I am making an error in the calculation? The final goal is to ensure that I put in 1A of current through each dipole.

• Nazanin
Subscriber

I have the same problem. I put 2 dipoles very close to each other and excite one of them with 1 watt and zero phase and the other is off (the power is set zero). then I change the port impedance for the unexcited dipole. as I change the port impedance, the current is changed significantly ( by integrating J over a defined line on port) but the active z on excited port does not change!!! even if I put negative impedance on the unexcited dipole, I see a huge difference in current; but, the Active z on the excited port does not change