The design of high-resolution radars which can operate in theater involves a careful consideration of the radar's radiated spectrum. While a wide bandwidth yields better target detectability and classification, it can also interfere with other devices and/or violate federal and international communication laws. Under the Army Research Laboratory (ARL) Partnerships in Research Transition (PIRT) program, we are developing a Stepped-Frequency Radar (SFR) which allows for manipulation of the radiated spectrum, while still maintaining an effective ultra-wide bandwidth for achieving good range resolution. The SFR is a forward-looking, ultra-wideband (UWB) imaging radar capable of detecting concealed targets. This paper presents the research and analysis undertaken during the design of the SFR which will eventually complement an existing ARL system, the Synchronous Impulse REconstruction (SIRE) radar. The SFR is capable of excising prohibited frequency bands, while maintaining the down-range resolution capability of the original SIRE radar. The SFR has two transmit antennas and a 16-element receive antenna array, and this configuration achieves suitable cross-range resolution for target detection. The SFR, like the SIRE radar, is a vehicle mounted, forward-looking, ground penetrating radar (GPR) capable of using synthetic aperture radar (SAR) technology for the detection of subsurface targets via 3D imaging. Many contradicting design considerations are analyzed in this paper. The selection of system bandwidth, antenna types, number of antennas, frequency synthesizers, digitizers, receive amplifiers, wideband splitters, and many other components are critical to the design of the SFR. Leveraging commercial components and SIRE sub-systems were design factors offering an expedited time to the initial implementation of the radar while reducing overall costs. This SFR design will result in an ARL asset to support obscured target detection such as improvised explosive devices (IEDs) and landmines.