Abstract: When facing micro-Doppler signals with relatively high micro-motion frequencies, the performance of existing modal decomposition algorithms is greatly reduced due to the limitations of interleaved signal properties and the empirical parameters of the algorithms. By utilizing the physical property that micro-Doppler signals can be expressed as multiple sinusoidal frequency modulation modes, and by unifying nonlinear frequency modulation decomposition algorithms with high-precision time-frequency spectrum technology, a sinusoidal frequency modulation mode decomposition algorithm for micro-Doppler signals is proposed. Based on the sparsity of the micro-motion frequency of micro-Doppler signals, the algorithm constructs a fractional trigonometric function basis that includes micro-motion frequency estimation, thereby improving the estimation accuracy of the instantaneous frequency characteristics of multi-component micro-Doppler signals. Simulation experiments verify that the proposed sinusoidal frequency modulation mode decomposition algorithm achieves a 3 dB improvement in output SNR compared to traditional intrinsic chirp component decomposition algorithms and exhibits stronger universality for targets with different micro-motion frequencies.