Field-Based Circuit Model of Acoustically Actuated Piezoelectric Antenna for Characteristic Evaluation and Array Applications

A field-based circuit model (FBCM) is proposed to reveal impedance, near-field, and far-field performance of acoustically actuated piezoelectric (PE) antenna by introduction of electromagnetic induction into PE equations and impedance analysis at the boundary. To make the model more practical, induced current on the PE antenna body is analyzed and near-field compression by the large permittivity of PE material is formulated. Closed-form expressions are built to conveniently evaluate model parameters. Furthermore, the FBCM method is validated by precise vehicles, and calculation results agree with the measurement with a maximum frequency error of 0.15% and a near-field magnitude error of 3.9 dB; all measured impedance and near-field components follow the characteristic described by FBCM. Finally, the radiation efficiency of a demonstrated PE antenna is calculated by FBCM to be 1.3e−9 for a single unit and 2.0e−9 for a PE antenna array, which is 5–67 times higher than that of a metallic electrical small antenna of the same size. The FBCM method can be an effective and convenient way for researchers to design and evaluate PE antennas in a short time.