For the Shunt mounted diode rectenna structure, the input is generally applied in 0-20 dBm range. The corresponding power levels make the threshold voltage to have a lesser impact on the performance of the circuit. The objective of this configuration is to minimize the internal loss of the rectifier diode used in the rectenna structure. The input and output filters should be dimensioned using the same optimization technique as for single series mounted diode rectenna topology. In such a situation, the structure can attain maximum conversion efficiencies of about 70% for an input power of +15 dBm.
There is a similar dependency with respect to the impendence of the load, which has an optimal load of 750 Ω for +15 dBm input power at a frequency of 2.45 GHz (Agbinya 2012). For shunt-mounted rectenna configuration, the maximum efficiency level is attained against +15dB input power and conversion efficiency exhibits dependency with respect to load impedance as shown in Pin vs. efficiency curve. It implies that shunt-mounted rectenna configuration with a particular resistance acts as a voltage source. Compared to single series mounted diode rectenna the shunt mounted diode exhibits a low efficiency for low power levels.
Additionally, by increasing the power levels above 15 dBm the efficiency will decrease rapidly due to the internal diode ohmic loss. Additional to the low-frequency rectification, an important application of the diode bridge (as shown in figure 8) is its use as rectenna in RF-DC conversion. The principle of full-length rectification entails the reinstitution of the complete incident wave at the load level complementary to half-wave rectifiers with characteristics whereby the load is disconnected for half the time from the source.
The key benefit of diode bridge topology is its greater power handling capability due to the application of diodes as a bridge. However, the application of diode bridge topology is limited as it cannot be adapted to low incident power levels. At the low power level, the input signal has to overcome the three thresholds thereby increasing the loss.
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