In the integrated application scenario of synthetic aperture radar (SAR) and communication, SAR imaging is typically implemented using the traditional range-Doppler algorithm (RDA). However, this method encounters geometric distortion in imaging scenarios with large squint angles. To address this issue, a synthetic aperture imaging method for OFDM signals based on the extended Omega-K algorithm (EWKA) is proposed. This method applies the traditional Omega-K algorithm to OFDM signal-based synthetic aperture imaging. After removing the cyclic prefix (CP) from the echo signals, two-dimensional pulse compression is performed in the range and azimuth directions. Phase shift compensation is applied to correct phase deviations caused by squint conditions.Subsequently, Stolt interpolation in the two-dimensional frequency domain is used to decouple higher-order phase coupling between the range and azimuth directions, and Doppler frequency offset compensation is performed to achieve the final two-dimensional imaging. Finally, simulation experiments on single-point and multi-point targets were conducted in both side-looking and large squint scenarios. Comparative simulation results show that, in side-looking scenarios, the EWKA-based imaging algorithm improves the azimuth PSLR from -12.32 dB to -17.024 dB, an enhancement of approximately 38.1%, while maintaining comparable range performance. In squint scenarios, the traditional RDA-based imaging algorithm suffers from defocusing and fails to achieve satisfactory imaging, whereas the EWKA-based algorithm maintains good focus. The simulation results verify the feasibility and effectiveness of the EWKA-based imaging algorithm under both side-looking and large squint conditions. The proposed EWKA-based OFDM signal synthetic aperture imaging algorithm not only resolves the defocusing issue encountered in traditional RDA-based methods in large squint scenarios but also enhances azimuth performance in side-looking scenarios, significantly expanding the applicability of OFDM signal-based synthetic aperture imaging.