Help need on Rectifier input frequency

[abdul.1991]

Hello all,

I am working on a Project RF energy harvesting, I need some help regarding the rectification process in this project.

I have antenna design for different frequencies, i.e 900MHz, 2.4GHz, Antenna receive those frequency signals and input to the rectifier, my question is how will rectifier behave for those frequencies.?? What is the rectifier response against those frequencies.

Thanks in advance.

 

[mrinalmani]

Normal fast recovery diodes will not work. Use Schottky barrier diodes (For frequencies upto 50GhZ)

 

[jiripolivka]

Hello all,

I am working on a Project RF energy harvesting, I need some help regarding the rectification process in this project.

I have antenna design for different frequencies, i.e 900MHz, 2.4GHz, Antenna receive those frequency signals and input to the rectifier, my question is how will rectifier behave for those frequencies.?? What is the rectifier response against those frequencies.

Thanks in advance.

At those UHF bands only detector or mixer Schottky diodes do rectify with a reasonable efficiency. The problem is that such Schottky diodes must have a small junction capacitance (typically measured in femto-Farads(, so the size of such junction is very small and does not allow a current larger than say 10 mA, and a typical breakdown voltage is 3...5 V. The RF power is thus limited to several mW.
Detectors connected to antennas (rectennas) suffer also by the impedance mismatch which varies with RF input power. Most of incident power is reflected back, so the efficiency is some 10 per cent.
Until someone invents a better rectifier, RF harvesting remains as poor as solar cells or worse.