This thesis studies the use of antenna coupled metal-insulator-metal (ACMIM) tunneling diodes for long wave infrared (LWIR) energy harvesting applications. Bow tie shaped ACMIM structures provide good polarization and bandwidth response, coupling the incident radiation to the demodulating MIM tunneling diode for power rectification. The use of geometric asymmetry at the junction (one tip flat, the other pointed) and the resulting electric field enhancement provides the necessary current-voltage (IV) relationship asymmetry. This geometric technique allows a simultaneous reduction in resistance and capacitance, improving frequency response. These results were confirmed by finite-element analysis of fabricated structures, and optimized for 10um LWIR radiation. During testing, the device IV plots became linear (yet responded better), due to the electric field formation of a shunt resistance across the junction. Equivalent circuit models of the ACMIM structure were developed to study the effects of this shunt and understand the increased performance through impedance matching.