We outline recent achievements in creating structural composite materials with controlled electromagnetic properties, as an integral part of a multifunctional material system. The electromagnetic response is tailored by incorporating within the material small amounts of suitably configured, periodically distributed, electric conductors to produce distributed electric inductance and capacitance. The small-scale response of the conductors can be homogenized to give overall macroscopic EM material properties at wavelengths that are orders of magnitude larger than the dimensions of the periodicity of the structure. Periodic arrays of inductive elements such as thin straight wires, loop-wires, coils, and other conductive thin metallic structures can modify the effective electric permittivity and the effective magnetic permeability of a composite and make it negative. I will discuss the process of design, analysis, manufacturing, and measurement of such composites. In particular, I will review the UCSD's work on the design, production, and experimental characterization of a 2.7 mm thick composite panels having negative refractive index between 8.4 and 9.2 GHz. I will also examine our work on a flat lens having a gradient variation of negative index of refraction that can focus in the 10GHz range, showing excellent agreement with full-wave simulations.