ziya,
you can refer to the vendor’s catalogue of those cables. Normally each cable is defined by a certain set of “physical charasteristics”, such as attenuation dB/m, weight, thickness, etc.
One of those characteristic is the “minimum bending radius”
Definition of the bending radius here : en.wikipedia.org/wiki/Bend_radius
In your case (double circle), you should use the “minimum radius for repeated bends”.
If you cannot find you cable vendor’s catalogue, you can refer to RFS catalogue (online) :
www dot rfsworld.com/index.php?p=289&l=1&mode=hierarchy
for 1/2″ : min radius repeated bends = 125mm (corrugated) or 32 mm (superflexible). Basically, even with the roughest 1/2″ jumper, you can do narrow circles of min. 25cm diameter (corrugated) or 7cm (superflexible).
Regards,