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A number of studies of WMAP and Planck have highlighted that the power at thelow multipoles in CMB power spectrum are lower than their theoreticallypredicted values. Possible angular correlation between the orientations ofthese low multipoles have also been claimed. It is important to investigate thepossibility that the power deficiency at low multipoles may not be ofprimordial origin and is only an observation artifact coming from the scanprocedure adapted in the WMAP or Planck satellites. Therefore, its alwaysimportant to investigate all the observational artifacts that can mimic them.The CMB dipole which is almost 550 times higher than the quadrupole can leak tothe higher multipoles due to the non-symmetric beam shape of the WMAP. In thispaper a formalism has been developed and simulations are carried out to studythe effect of the non-symmetric beam on this power transfer. It is interestingto observed that a small but non-negligible amount of power from the dipole canget transferred to the quadrupole and the higher multipoles due to thenon-symmetric beam. It is shown that in case of WMAP scan strategy the shape ofthe quadrupole coming due to this power leakage is very much similar to theobserved quadrupole from WMAP data. Simulations have also been carried out forPlanck scan strategy. It is seen that for Planck scan strategy the powertransfer is not only limited to the quadrupole but also to a few higher lowmultipoles. Since the actual beam shapes of Planck are not publicly availablewe present results in terms of upper limits on asymmetric beam parameters thatwould contaminate of the quadrupole power at the level of $1\mu K$.

Leakage of power from dipole to higher multipoles due to non-symmetric WMAP beam