fparveen
Junior Member level 3
Hello,
I am simulating a vivaldi antenna of size 30.2 X 44.4 mm^2 .
I calculated the far-field distance at 4 GHz to be 53 mm, using the 2D^2/lambda formula from Balanis, where D is largest dimension , i.e. 44.4 mm.
In simulation, I plotted the near field (both in CST and HFSS). I expected to get the far field like pattern after 53 mm. But actually the far field like pattern starts appearing from much longer distance than that calculated from this formula. I am getting far-field like pattern from around 30 cm (300 mm), which is much larger than 53 mm calculated from the equation.
Can anyone verify if this is usual? Or is there any mistake in my far field distance calculation using this equation?
Thanks
I am simulating a vivaldi antenna of size 30.2 X 44.4 mm^2 .
I calculated the far-field distance at 4 GHz to be 53 mm, using the 2D^2/lambda formula from Balanis, where D is largest dimension , i.e. 44.4 mm.
In simulation, I plotted the near field (both in CST and HFSS). I expected to get the far field like pattern after 53 mm. But actually the far field like pattern starts appearing from much longer distance than that calculated from this formula. I am getting far-field like pattern from around 30 cm (300 mm), which is much larger than 53 mm calculated from the equation.
Can anyone verify if this is usual? Or is there any mistake in my far field distance calculation using this equation?
Thanks