Design and development of batch fabricatable metal–insulator–metal diode and microstrip slot antenna as rectenna elements

Thin-film Ni-NiO-Cr metal–insulator–metal (MIM) tunnel diodes with 1 μm2 contact area and 1–3 nm insulator layer (NiO) are fabricated for high sensitive far-infrared (IR) detection. Also, a 2.5 GHz microstrip slot antenna is fabricated on a FR-4 substrate and integrated with a commercially available surface mount zero bias Schotky diode. Asymmetric current–voltage (I–V) characteristics of the MIM tunnel diode is observed with a significant degree of non-linearity. Additionally, the sensitivity of the MIM diode is determined to be 5 V−1 at Vbias of 0.1 V. For the antenna coupled detector circuit, the radiation patterns, scattering parameters, output voltage and sensitivity are determined experimentally. Further, when the slot antenna is coupled with the schottky diode detector, a rectified output voltage of 56 mV is obtained by radiating the device with a low frequency tube antenna.