When a flexible antenna is bent, its physical structure changes, altering the distribution of current and voltage along the antenna elements. This can cause changes in the electromagnetic fields around the antenna, resulting in changes to the radiated power and directionality of the antenna.              
In some cases, bending can cause a significant shift in the resonant frequency of the antenna, which can impact its performance in specific frequency bands (see the visualization below).

Another effect of bending is changes to the antenna's impedance. Bending can cause changes in the antenna's effective length, leading to impedance mismatches that can result in signal loss and reduced performance. How do we predict the effects of bending? We use advanced simulation tools to model and optimize the antenna's design for different bending angles!