We present a description of the reorientation of the macroscopic polarization P S under a switching field in a ferroelectric liquid crystal assuming the direction of P S is spatially uniform but time-dependent throughout the sample. The driving torques are then the linear ferroelectric coupling and the quadratic dielectric torques. If the theory is correct, some of the important parameters of a FLC may be determined in a single experiment, such as the spontaneous polarization P S , the switching delay t m , the switching time t, the orientational viscosity g and the dielectric anisotropy e a . The measurements are performed using new compound, as a function of temperature with different field strengths and sample thicknesses. The experiment appears to be poorly fit by the so-called 'rigid' hypothesis leading to the conclusion that the switching of polarization is not uniform but rather starts locally from orientational defects and propagates quickly throughout the sample. This reinforces the view that the driving torque equation is nothing but the Sine-Gordon equation reminiscent of soliton propagation.

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In this study, the authors propose a new numerically stable digital predistorter for the linearisation of RF Power amplifiers. The proposed predistorter is based on the parameterised Gegenbauer polynomials that can be optimised for maximum predistorter efficiency and stability under different input signal distributions. The robustness and the efficiency of the proposed predistorter are experimentally demonstrated and compared to the ones of previously published polynomial model‐based predistorters. The obtained results revealed exceptional numerical stability regardless of the input signal statistics, making the proposed predistorter suitable for the linearisation of multimode and broadband non‐linear wireless transmitters.

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