| 摘要 |
An antenna 100 that acts as an RF choke for use in a dual band radio 120, the antenna comprising: a winding 150 extending longitudinally; a tuning cylinder 160, located substantially coaxially with the winding; and a capacitor 140 coupled to the base of the winding. The winding 150 may be arranged within the cylinder 160, or the cylinder 160 may be arranged within the winding 150; in both embodiments the cylinder and winding are separated by a small distance. The cylinder 160 has a preferable length, and the longitudinal position of the cylinder 160 relative to the winding 150 is selectable to determine the performance of the antenna. This provides the advantage that the antenna height may be kept desirably low, the bandwidth of the antenna may be improved, and interaction with the user may be reduced by restricting the magnetic field resulting in better overall antenna performance. |
