The code is wrong because in Tradestation the function atan() returns degrees while in PineScript returns radians.
To fix the problem the result of the function in degrees must be converted into radians multiplying it by 180/pi.
You must create de variable pi= 3.14159265359 first and
line 50 mesaPeriod:= 360/atan(Im/Re) must be rewritten into mesaPeriod:= 2*pi/atan(Im/Re)
line 72 phase:=atan(Q1/I1) must be rewritten into phase:= 180/pi * atan(Q1 / I1)
To fix the problem the result of the function in degrees must be converted into radians multiplying it by 180/pi.
You must create de variable pi= 3.14159265359 first and
line 50 mesaPeriod:= 360/atan(Im/Re) must be rewritten into mesaPeriod:= 2*pi/atan(Im/Re)
line 72 phase:=atan(Q1/I1) must be rewritten into phase:= 180/pi * atan(Q1 / I1)
note: 360º = 2*pi radians
The chart should look something like this