Abstract: Low frequency broadband signals have advantages in improving radar target recognition ability. To determine the ground reflectance of broadband signal at low altitude, the ground reflectance of different frequency points of narrowband is used to compose the equivalent ground reflectance of broadband signal based on ground reflection model. The relationship between ground reflectance and ground characteristics (relative dielectric constant, conductivity), grazing angle, and polarization characteristics were discussed in detail. The reflectance in typical environment was verified using the method of antenna pattern test at low altitude. Results show that the reflectance simulation model was effective, and the model provides theoretical basis for broadband radar target detection.

Key words: broadband, low altitude, antenna pattern, ground reflection