For example, a first Enhanced Directional Multi-Gigabit (DMG) (EDMG) station (STA) may be configured to exchange first and second Beam Refinement Protocol (BRP) setup frames with a second EDMG STA to initiate a BRP Transmit Sector Sweep (TXSS) over an aggregated channel bandwidth including an aggregation of a primary channel and a secondary channel in a frequency band above 45 GHz; during the BRP TXSS, transmit a plurality of BRP frames to the second EDMG STA over the primary channel and the secondary channel according to an EDMG control mode; determine a transmit beamforming configuration over the aggregated channel bandwidth based on BRP feedback from the second EDMG STA; and transmit an EDMG Physical Layer (PHY) Protocol Data Unit (PPDU) to the second EDMG STA over the aggregated channel bandwidth based on the transmit beamforming configuration.