A narrow band antenna is configured to guide a munition toward a target location during a flight of the munition from a launch location toward the target location. The antenna has a first mode of operation operable during a first portion of the flight at a first bandwidth, and a second mode of operation operable during a second portion of the flight at a second bandwidth, the second bandwidth being a harmonic of the first bandwidth, and may be a third harmonic of the first bandwidth. The method includes transmitting a target location information to the munition in the first bandwidth during the first portion of the flight and then transmitting the target location information to the munition in the second bandwidth during the second portion of the flight. The first band may be X-band and the second band may be Ka-band.