A CST Microwave Studio developer uses the software to simulate electromagnetic fields and analyze their effects. They create models and simulations of high-frequency applications, such as antennas, filters, or circuits. Their work aids in the design and optimization of these applications, helping to predict their behavior and performance before physical prototypes are made. They also troubleshoot and solve electromagnetic interference and compatibility issues. They often collaborate with engineers and scientists, using their simulations to inform design decisions and contribute to research and development efforts in fields like telecommunications, aerospace, healthcare, and defense.