The LFR is materialized by the combination of a controlled TVT or TVG and a signal-processing circuit (SPC), which controls the coupling network, such that equations above are obeyed. Methods of loss reduction by the transferring of energy to the source that powers the circuit are well known; however, these methods are usually applied for recovering the energy trapped in storage elements. In those circuits, there is not continuous control of the coupling networks that transfer the recovered energy to the source. In our method, the required resistive characteristic is obtained by the continuous control of the loss-free, storage-less two ports.
