The electrosurgical systems and associated methods of the present disclosure perform narrowband real impedance control for precise treatment of tissue in electrosurgery. The electrosurgical systems include an electrosurgical generator that includes an output stage configured to generate electrosurgical energy to treat tissue, a plurality of sensors configured to sense voltage and current waveforms of the electrosurgical energy, and a controller coupled to the output stage to control the generated electrosurgical energy. The controller includes a signal processor that (I) determines a complex-valued voltage and a complex-valued current based on the voltage waveform and the current waveform sensed by the plurality of sensors using a plurality narrowband filters, and (2) calculates a real part of an impedance of the tissue using the complex-valued voltage and the complex-valued current. The controller also includes an output controller that controls the output stage based on the calculated real part of the impedance of the tissue.
