The proliferation of Internet of Things (IoT) devices has brought forth the demand for sustainable and self-powered solutions. Energy harvesting from ambient radiofrequency (RF) signals has emerged, as a promising approach, to address the power requirements of embedded IoT devices. Rectenna circuits, combining antennas and rectifiers, play a crucial role in efficiently capturing and converting RF energy into usable electricity. This paper presents an overview of recent trends and developments in rectenna circuits for energy harvesting, focusing on innovations tailored for embedded IoT applications. The article explores key design considerations, fabrication techniques, and performance characteristics of these cutting-edge rectenna circuits, highlighting their potential to revolutionize the autonomy and energy efficiency of embedded IoT systems.