Acoustically coupled antenna
Is Version Of
An acoustically coupled antenna which can be configured as a transmitting or receiving antenna for coupling between an electrical circuit (transmitter or receiver) and an electromagnetic propagating medium such as the atmosphere. The antenna is a two port device in which one port is connected to the electrical circuit and the second port includes a transducer which interfaces (radiates or receives) electromagnetic energy with the propagating medium. The ports are acoustically coupled to each other by forming the device as a stacked crystal filter with three conductive electrodes separated by two piezoelectric resonating elements. The first port comprises two of the electrodes separated by one of the piezoelectric elements, and the second port shares the electrode separating the two piezoelectric elements, and further includes the second piezoelectric element and the final electrode. The electrical signals in the bandwidth of the antenna at the two ports are acoustically coupled by the coupled resonators of the stacked crystal filter for translating energy from one port to the other while providing electromagnetic isolation by virtue of the acoustic coupling.