The Advanced Concepts Laboratory is a recognized leader in the design and analysis of novel electromagnetic structures that span frequencies from VLF to the visible spectrum. ACL pioneered the development of genetically optimized ultra-wideband apertures (up to 30:1 bandwidth) and has applied its antenna expertise to designing electrically-small antennas, conformal antennas, and three-dimensional radiators. ACL was an early innovator in the area of reconfigurable antennas, which have the capability of being field-reprogrammable to dynamically adapt antenna characteristics to the mission. ACL designs custom radome and frequency-selective surfaces to isolate EM structures from the outside environment. To support these efforts, ACL develops and maintains a suite of high-fidelity computational electromagnetic tools that execute on high-performance computing clusters.