[ANT]”Is a flexible antenna (a wire) simply soldered close to the RF-Plane sufficient aa antenna – or a perpendicular soldered stiff wire with quarter wavelength over a ground plane leads to the best result?

An wire (flexible or stiff) can be used as antenna and work well. For flexible wire you should find a way to fix it to get repeatable performance. If the wire is perpendicular on PCB/ground plane everything should work very nice. If wire is folded over ground plane, the antenna might need to be tuned. This is most normally done by reducing wire length slightly below a quarter wavelength

Last Update: August 8, 2017