ACTIVE FILTER WITH DUAL RESPONSE

摘要

Active filter with dual response, comprising a main conductive line between an input port (1) and an output port (2), consisting of an input conductive section, an output conductive section, and an inductance network in series between the input and output conductive sections, the inductance network being coupled to LC resonators, an LC resonator being connected to each junction point between two network inductances, and at least one negative resistance (RN) in series with one of the resonators, wherein the main conductive line, the LC resonators and the negative resistance(s) form an active low-pass filter with a cut-off frequency fc, wherein the active filter comprises a conductive auxiliary line (20), having one end (21) at the filter input side, connected to an electrical ground, and forming a resonator with a resonant frequency fr, less than the cut-off frequency fc of the low-pass filter, the conductive auxiliary line extending from this end, parallel to the main conductive line, and forming by coupling with the main conductive line a rejection filter tuned substantially at said resonant frequency in the low-pass filter bandwidth.