An ultra-massive phased array can be deployed in high-throughput millimeter-wave (mmWave) communication systems to increase the transmission distance. However, when the signal bandwidth is large, the antenna array response changes with the frequency, causing beam squint. In this paper, we investigate the beam squint effect on a high-throughput mmWave communication system with the single-carrier frequency-domain equalization transmission scheme. Specifically, we first view analog beamforming and the physical channel as a spatial equivalent channel. The characteristics of the spatial equivalent channel are analyzed which behaves like frequency-selective fading. To eliminate the deep fading points in the spatial equivalent channel, an advanced analog beamforming method is proposed based on the Zadoff-Chu (ZC) sequence. Then, the low-complexity linear zero-forcing and minimum mean squared error equalizers are considered at the receiver. Simulation results indicate that the proposed ZC-based analog beamforming method can effectively mitigate the performance loss by the beam squint.