Multi-layered stacked dielectric devices provide spectral shaping for filtering or beam emission purposes. An algorithm, based on the genetic algorithm optimization routine and the transmission line model of dielectric slabs, was used for the design process in two projects. The first focused on the design and fabrication of a periodic structure for bandpass filtering at millimeter-wave (aperiodic demonstrated in simulation). The fabricated structure was measured with a center frequency of 57 GHz with an insertion loss of less than 1 dB, and a 3-dB bandwidth of 4.5 GHz. The second focused on the design, fabrication, and thermal testing of a 7-layer aperiodic thermal emitter consisting of alternating layers of silicon and silicon dioxide and backed by a metallic ground plane. An emittance of 0.7 and Q-factor of 113 is achieved at 70°C. Superior performance of aperiodic structures over their periodic counterparts is demonstrated using numerical examples.