Designing sparse frequency waveform with low range sidelobes for HFSWR

Sparse frequency waveform with narrow stopbands sparsely distributed over a wide spectrum band is desired for high frequency surface wave radar (HFSWR). However, it gives rise to high range sidelobes. To solve this problem, a method for designing sparse frequency waveform with low range sidelobes is proposed in this paper. The fitness function is constructed to design phase codes according to the following criteria: minimizing the ratio of the energy in stopbands to that in passbands with finite power constraint and minimization of range sidelobes. The particle swarm optimization-simulated annealing (PSO-SA) algorithm, by combing PSO with SA, is introduced to search the optimal unimodular solution. Simulation results are presented to show the effectiveness and flexibility of the proposed method.