Design considerations for low-power, high-sensitivity rectennas

Through analysis it is found that the only steps available to maximize the voltage at the input of a rectifying and voltage multiplication circuit for a given low level of power available from the antenna are: Design the rectifier/multiplier circuit for a minimum real part of the input admittance and conjugate match the antenna to the rectifier/multiplier circuit. Use antenna miniaturization up to a level that still yields an acceptable radiation efficiency and start from a small loop antenna.