PURPOSE:To enhance the RF/DC conversion efficiency by selecting a distance from a rectifier means till a harmonic interruption means to be nearly an odd number of multiple of a 1/4 wavelength at the cut-off frequency. CONSTITUTION:The rectenna is provided with an input terminal TIN an input filter section FIN, a rectifier means 1, an output filter section FOUT, an output terminal TOUT, and open stubs 111-117 to interrupt 2nd-5th harmonics. Then a distance (line length) between the rectifier means 1 and the open stub to interrupt an n-th harmonic is selected to be an odd number of multiple of a 1/4 wavelength lambdag of the n-th harmonic. The open stub 131 whose length is 1/4 wavelength of a fundamental wave is short-circuited with respect to the fundamental wave whose fundamental frequency is f0 and open to its DC component. The open stub 133 whose length is 1/8 wavelength of the fundamental wave is short-circuited with respect to the 2nd harmonic wave whose frequency is 2f0, and the open stub 135 whose length is 1/16 wavelength of the fundamental wave is short-circuited with respect to the 4th harmonic wave whose frequency is 4f0. As a result, not only the fundamental wave but also its harmonic components are power-converted.