Abstract: As a key component of radar systems, the RF front-end directly impacts the overall system performance. This paper presents a design scheme for an L-band ultra-wideband RF front-end with dual-mode transmission functionality. The article first clarifies the design requirements, then elaborates on the overall design scheme in detail, focusing on the analysis of critical modules such as the transmit chain, power modulation circuit, and switch-limited low-noise amplifier, while also introducing the overall layout design. The RF front-end features a compact design with well-organized signal chains. Test results demonstrate that the main performance metrics of the design have been largely achieved.