Compact Rectifiers With Ultra-wide Input Power Range Based on Nonlinear Impedance Characteristics of Schottky Diodes

Two high-efficiency radio-frequency (RF) rectifiers with extended input power range are proposed by taking the advantage of nonlinear impedance characteristics of diodes. Each rectifier consists of two subrectifiers that operates at high- and low-power levels, respectively. A nonlinear power division strategy is applied to the input power level without any power dividers or couplers. A λ/8 transmission line is introduced to compensate the imaginary part of diode impedance. A λ/4 transmission line is applied to reverse the diode impedance variation with respect to the input power. Two rectifiers operating at 2.45 GHz are fabricated and measured. Rectifier I shows a RF-dc power conversion efficiency exceeding 50% over an input power range of 23.3 dB (from 6.5 to 29.8 dBm), with maximum efficiency 74.5% at 27 dBm input power. Rectifier II shows an input power range exceeding 50% over 31 dB (-1 to 30 dBm) with maximum efficiency of 68.5% at 28 dBm.