The radio emission from air showers is beamed forward during shower development and produces a characteristic footprint on the ground. This emission imprints the content of electromagnetic particles in the cascade and, via measurements with radio antennas, can be used to study cosmic ray and particle physics. Compared to that of particle detectors, the radio footprint is more complex, generally including a Cherenkov ring as well as azimuthal asymmetries in the shower plane due to interference. Understanding the structure of this emission and the footprint of the ground is important for an accurate description of the electromagnetic content in air showers and has been used directly in likelihood-based reconstructions. In this work, we describe an analytical model for the distribution of signal in the frequency band from 70-350 MHz based on CoREAS simulations for the South Pole location. We model both the geomagnetic and charge excess emissions in this band and characterize the evolution of the respective footprints for showers which reach a maximum size both above and below ground.