Multicarrier technology is widely used for improving the performance of beampattern synthesis in frequency diverse array multiple-input and multiple-output (FDA-MIMO) Radar. However, how to use multicarrier technology to achieve highly focussed beampattern synthesis is still an open problem. To this end, the authors first establish the system model of FDA-MIMO radar with multicarrier transmission and analyse the parameters influencing beampattern synthesis by Cramér-Rao lower bound derivation. It can be recognised that frequency increments and multicarrier distribution are key parameters hindering highly focussed beampattern synthesis. On top of the investigation, a simple yet effective Multidimensional Non-linear Frequency Component, named multidimensional frequency components (MNFC), is proposed for forming a highly focussed beam. Specifically, MNFC is a two-dimension frequency component for FDA-MIMO radar. The first dimension is the frequency increment weighted by the Dynamic Taylor Window Function that effectively decouples the joint-range-angle beampattern. The second dimension is a non-linear multicarrier weighted by Log with a Linear Coefficient for further optimising dot-shaped beampatterns for target indication with high precision. Finally, numerical simulations and comparative experiments are performed to validate the superiority of the MNFC in beampattern synthesis.