| 摘要 |
PURPOSE: To provide a multifrequency tuning-type loop antenna device which can collectively be tuned to plural frequencies mainly in the broadcasting and communication of long/medium wave bands. CONSTITUTION: A loop antenna 1 constituted of the coaxial cable 2 having prescribed length and formed into a loop shape is electromagnetically and closely coupled with a multifrequency tuning circuit 5 provided with n-pieces of serial resonance circuits through a high frequency transformer T1 having the winding ratio so that the number of a primary side windings is made larger than the number of secondary side windings. Tuning output induced by the loop antenna 1 is fetched from an output terminal 6 through a high frequency transformer T2 connected to the loop antenna 1. In this way, since the change of the resonance frequencies becomes less in the loop antenna 1 and the multifrequency tuning circuit 5 due to the influence of mutual circuit conditions, the multifrequency tuning can easily, stably and collectively be executed in the plural resonance frequencies which are set in the respective serial resonance circuits. |
