  Variations of the antenna primary beam (PB) pattern as a function of time,
frequency and polarization form one of the dominant direction-dependent effects
at most radio frequency bands. These gains may also vary from antenna to
antenna. The A-Projection algorithm, published earlier, accounts for the
effects of the narrow-band antenna PB in full polarization. In this paper we
present the Wide-Band A-Projection algorithm (WB A-Projection) to include the
effects of wide bandwidth in the A-term itself and show that the resulting
algorithm simultaneously corrects for the time, frequency and polarization
dependence of the PB. We discuss the combination of the WB A-Projection and the
Multi-term Multi Frequency Synthesis (MT-MFS) algorithm for simultaneous
mapping of the sky brightness distribution and the spectral index distribution
across a wide field of view. We also discuss the use of the narrow-band
A-Projection algorithm in hybrid imaging schemes that account for the frequency
dependence of the PB in the image domain.
