A Novel Quartz Clock With Integrated Wireless Energy Harvesting and Sensing Functions

There has been an increasing demand for smart devices and smart furniture for home automation, monitoring, and security applications. In this paper, we present a novel method of integrating the function of wireless energy harvesting from ambient RF signals to a conventional quartz clock for home applications. The most attractive feature is that the clock itself is used as the power receiving device, thus no additional antennas are needed. A simple rectifier is designed to directly match with the clock antenna and rectify the power captured by the clock. As a design example, a clock rectenna using the proposed new idea achieves good energy conversion efficiency (up to 65%) over its operating frequency bands at around 1.4-1.5, 1.9-2.1, and 2.4-2.8 GHz, respectively. Moreover, a wireless environmental sensor is integrated with the clock and powered by using the harvested power from the proposed clock rectenna. This novel design greatly expands the functionality of the quartz clock without affecting its size and appearance. We believe that the proposed energy harvesting quartz clock could be adopted for smart home applications.