Optimum design and fabrication of volumetric graded substrate for a broad band miniature antenna

Printed antennas suffer from narrow bandwidth and large size as the frequency is lowered. A novel design procedure based on the integration of full wave FEA and the SIMP design method (Sigmund, O. Computer methods in applied mechanics and engineering, vol.190, p.6577-604, 2001) employing sequential linear programming for the optimization was introduced. The capability was demonstrated by achieving a 250% BW improvement for a probe fed patch antenna through the design of only the dielectric substrate while the size is kept constant. The design is filtered and solidified to achieve a manufacturable state. The fabricated final design using thermoplastic green machining is indeed a remarkable demonstration of our ability to design and manufacture novel material compositions with dramatically new applications.