Optimization of a 5.8-GHz rectifier considering ripple amplitude and DC-voltage pattern

In this article, several aspects of the rectifier which has not been analyzed in recent rectenna related papers so far are studied. First, dc-voltage pattern is evaluated using oscilloscope and the ripple amplitude of the dc-voltage is calculated. Second, a basis for decision of capacitance as a dc-pass filter is provided, and the measurement result is obtained. Third, impedance matching condition of the rectifier with series configuration is considered and the parasitic cancellation circuits are designed at not only output but also input of the packaged Schottky diode to improve RF-to-DC conversion efficiency and decrease ripple amplitude. The proposed 5.8-GHz rectifier shows RF-to-DC conversion efficiency of 60.6 % at an input power level of 9 dBm and 1.3 KΩ load without dc-pass capacitor with 0.28 % of ripple amplitude.