Nowadays, numerous devices to manipulate high frequencies for various applications are rapidly being investigated. Among them, nano-antennas for energy harvesting application at thermal radiation spectrum received most attention. A potential of versatile rectangular patch with perturbation slit tunnel that can collect electrical field energy is studied. The antenna performances are defined over field strength and current responses. The electrical field concentrated at the slit junction can be tuned by verifying the perturbation slit parameters. The electrical field amplitude of approximately 110 V/m is achieved with slit length of 1.0 µm. The field then can be guided out through the tunnel with some amplitude degradation in order to be integrated with metal-insulator-metal diode for energy conversion. The diode current obtained inside the insulator layer is compared with published results and it performs outstandingly. It was found that the proposed antenna exhibits promising performances that is suitable as an efficient energy harvesting device.