Suppression of Cross-Band Scattering by Using Sleeve Loads

A method to suppress cross-band scattering is presented in this letter. A two-antenna system is analyzed, which consists of a lower-band (LB) dipole and a higher-band (HB) dipole. A pair of sleeves is loaded on the arms of the LB dipole. The cross-band scattering between the HB and LB antennas close to each other usually deteriorates the pattern of the HB antenna. In the proposed antenna system, the sleeves loaded on the arms of the LB dipole are used to suppress the induced current on the LB antenna and reduce the cross-band scattering in the two-dipole system, which restores the radiation pattern of the HB antenna. A prototype of the proposed antenna system is fabricated and measured. The results show that the maximum radiation direction of the HB antenna is changed from a maximum of 24
$^\circ$
back to 0
$^\circ$
in the
$H$
-plane.