Phased array (PA) radar is one of the most popular types of radar. In contrast to PA, the frequency diverse array (FDA) is a potential solution to suppress range-related interference because of its time-range-angle-dependent beampatte. However, the range-angle coupling inherent in the FDA transmit beampatte may degrade the output signal-to-interference-plus-noise ratio (SINR). We propose a dot-shaped beamforming method based on the analyzed four subarray-based FDAs and subarray-based planar FDAs using a sinusoidally increasing frequency offset with elements transmitting at multiple frequencies. The numerical results show that the proposed approach outperforms the existing log-FDA with logarithmical frequency offset in transmit energy focus, sidelobe suppression, and array resolution. Comparative simulation results validate the effectiveness of the proposed method.