A Tunable Matrix Capacitive Impedance Matching Network for Electroacoustic Transduction Systems

In order to achieve efficient power transmission between the transducer and the power amplifier, and to solve the problem of acoustic wave distortion in the transmission, this paper proposes a tunable matrix capacitive impedance matching network (TMCIMN) for the Electroacoustic Transduction System (ETS). Firstly, the circuit model of the giant magnetostrictive transducer (GMT) was analyzed, and a method for fitting its load impedance was proposed. Subsequently, the TMCIMN topology, working principle, and matching range were introduced. This network implements controlled switching of matrix capacitors across operational frequency bands, enabling wideband efficient power transmission. To solve the amplitude-frequency response distortion in transducer sound waves, a pre-distortion method based on finite impulse response (FIR) filter frequency compensation was proposed. This method estimates the system impulse response using an equalization algorithm. The equalizer pre-processes the reference signal to compensate for missing frequency components and suppress excessive ones, thereby improving the sound output linearity. Simulation and experimental results demonstrated that, compared to traditional static impedance matching networks, the proposed method combines dynamic bandwidth matching switching with acoustic distortion compensation capability, achieving over 8-fold bandwidth expansion.