International Journal of Antennas and Propagation / 2013 / Article / Tab 2

Review Article

Comparative Study of Antenna Designs for RF Energy Harvesting

Table 2

Various antenna shapes and the associated harmonic rejection

FigureShapeFreq.Harmonic rejectionGainConversion efficiency

4(a)Circular patch with slots on the diameter2.45 GHzUnbalanced slots achieve second harmonic rejection3.36 dBic CP gainEfficiency would reach 53% and 75% with 1 K resistor load under ANSI/IEEE uncontrolled and controlled RF human exposure limit, respectively.
4(b)Microstrip circular sector antenna2.4 GHzCircular sector antenna with sector angle of 240° and inset feeding point at 30° from the edge avoids harmonic radiation4.677 dBiMaximum efficiency of 77.8% is achieved with a load resistor of 150 Ω and input power of 10 dBm
4(c)Rectangular patch with DGS2.45 GHzAn optimized length of the feeding line and DGS are used to reject the second and third harmonics6.4 dBConversion efficiency is 74% using a 1300  load resistor at a power density of 0.3 mW/cm2
4(d)U-shaped slot in middle surface of inset-fed rectangular patch antenna2.4 GHzU-slot antenna with inset feeding suppresses the harmonics6.96 dBiNot specified