| 摘要 |
<p>An antenna utilizing an overmoded configuration for coupling energy in a predetermined frequency band between an electrical circuit and a propagating medium. The antenna (20) includes a first thin film resonator (30) having a first pair of electrodes (32, 33) and a first thin film piezoelectric element (34) interposed between the first pair of electrodes, with the first thin resonator coupled to the electrical circuit. A second thin film resonator (31) includes a second pair of electrodes (35, 36) and a second thin film piezoelectric element (37) interposed between the second pair of electrodes, the second thin film resonator being operable for interfacing between the antenna and the propagating medium. A delay element (26) interposed between the first and second thin film resonators has a thickness substantially equal to a multiple of one-half wavelength of a desired frequency in the predetermined frequency band for acoustically coupling energy in the predetermined frequency band between the first and second thin film resonators. Alternatively, the delay element can have a thickness of a multiple of one-half wavelength plus one-quarter wavelength so that the delay element acts as an impedance inverter.</p> |
