I have a load measured by network analyzer as below, at 500kHz its impedance is 234.72 - j*1173.2, and I am targeting to match its impedance to 50 Ohm through impedance matching technique.

as the first step, I want to transfer the real part of impedance to 50 Ohm, and in the Smith chart tool I found using a 1:0.46 transformer can transfer the impedance from 234-j*1173(point : DP1) to 50-j*253(point : TP2)

since 1:0.46 is about 2:1, I found a 2:1 transformer "Coilcraft UA7962" ( https://forum.allaboutcircuits.com/forums/general-electronics-chat.5/post-thread , used in DC/DC switching converter), insert the transformer between network analyzer and the load then measure again, but the load impedance is transferred to 6+j*273, real part is "6" which is far from the expected "50".

then I tried another transformer "Mini-circuits TC4-6TG2+" ( https://www.minicircuits.com/WebStore/dashboard.html?model=TC4-6TG2+ , used in the RF field, note its Ohm ratio is 4:1 means turns ratio is 2:1)

but the impedance is transferred to 156+j*92, again, the real part is far from the target 50 Ohm

I know there must be error between theoretical simulation and the real world, however, the above result shows not only the error is large, but also the behavior of a transformer is far from simulation.

Please give me some instruction about what's wrong in my tests, am I using the wrong transformers ? is the error caused by unavoidable test setup error ? or the other reasons ?

I have no idea about what would be the next step, any suggestion would be highly appreciated, thanks.