A theoretical study examines the behaviour of a microelongated plate subjected simultaneously to electromagnetic fields, thermal gradients and a gravitational field, within the dual phase lag (DPL) framework. The work addresses thermoelastic wave propagation in a deformable medium with microstructure, where the microelongation variable adds internal degrees of freedom that modify the mechanical response compared with a classical plate.

The DPL model generalises Fourier's law by introducing two time delays, one for the heat flux and one for the temperature gradient, allowing heat transfer to be described at very short time scales without incurring the paradox of infinite propagation speed of classical conduction. Combining it with the equations of thermoelasticity and with electromagnetic interaction, the resulting system couples displacements, microelongation, temperature and electric and magnetic fields in a set of coupled differential equations.

Including the gravitational field adds a stability term that influences phase velocities and wave attenuation. The analysis yields dispersion relations and examines how the medium parameters, thermal delays and the intensity of the external fields modify the dynamic behaviour of the plate. The effect of microelongation on the vibration modes and the stability of the system is examined in particular.

Such models are of interest in microelectromechanical (MEMS) applications, sensors and structures subjected to demanding multi-physical environments, where thermal, electromagnetic and gravitational effects cannot be treated separately. The DPL framework is particularly relevant for describing ultrafast heating processes and the dynamic response of thin plates at microscopic scales.