An active beam scanning antenna , comprising: a plurality of radiating units that are configured to transmit and receive signals in a first frequency band, each radiating unit including a plurality of radiating elements; at least one array of radiating elements that are configured to transmit and receive signals in a second frequency band that is different than the first frequency band; a calibration circuit board configured to calibrate the plurality of radiating units operating in the first frequency band, the calibration circuit board including: a plurality of transmission line segments that are connected to the respective radiating units ; a plurality of couplers that are provided along the respective transmission line segment ; and a filter coupled along and associated with each respective transmission line segment ; and wherein: each filter comprises a first filter line branch that is connected to its associated transmission line segment at a first connection point, and a second filter line branch that is connected to its associated transmission line segment at a second connection point, the first and second connection points at spaced apart locations along the associated transmission line segment , wherein each first filter line branch is on a first side of a respective one of the couplers and each second filter line branch is on a second side of the respective one of the couplers . a plurality of radiating units that are configured to transmit and receive signals in a first frequency band, each radiating unit including a plurality of radiating elements; at least one array of radiating elements that are configured to transmit and receive signals in a second frequency band that is different than the first frequency band; a calibration circuit board configured to calibrate the plurality of radiating units operating in the first frequency band, the calibration circuit board including: a plurality of transmission line segments that are connected to the respective radiating units ; a plurality of couplers that are provided along the respective transmission line segment ; and a filter coupled along and associated with each respective transmission line segment ; and wherein: each filter comprises a first filter line branch that is connected to its associated transmission line segment at a first connection point, and a second filter line branch that is connected to its associated transmission line segment at a second connection point, the first and second connection points at spaced apart locations along the associated transmission line segment , wherein each first filter line branch is on a first side of a respective one of the couplers and each second filter line branch is on a second side of the respective one of the couplers . a plurality of transmission line segments that are connected to the respective radiating units ; a plurality of couplers that are provided along the respective transmission line segment ; and a filter coupled along and associated with each respective transmission line segment ; and wherein: each filter comprises a first filter line branch that is connected to its associated transmission line segment at a first connection point, and a second filter line branch that is connected to its associated transmission line segment at a second connection point, the first and second connection points at spaced apart locations along the associated transmission line segment , wherein each first filter line branch is on a first side of a respective one of the couplers and each second filter line branch is on a second side of the respective one of the couplers . <EOS>