We present results of deep polarization imaging at 1.4 GHz with the Dominion Radio Astrophysical Observatory as part of the DRAO Planck Deep Fields project .
This deep extragalactic field covers 15.16 deg ^ { 2 } centered at \alpha _ { 2000 } = 16 ^ { { h } } 14 ^ { { m } } and \delta _ { 2000 } = 54 \arcdeg 56 \arcmin , has an angular resolution of 42 \arcsec \times 62 \arcsec at the field center , and reaches a sensitivity of 55 \mu Jy beam ^ { -1 } in Stokes I and 45 \mu Jy beam ^ { -1 } in Stokes Q and U .
We detect 958 radio sources in Stokes I of which 136 are detected in polarization .
We present the Euclidean-normalized polarized differential source counts down to 400 \mu Jy .
These counts indicate that sources have a higher degree of fractional polarization at fainter Stokes I flux density levels than for brighter sources , confirming an earlier result .
We find that the majority of our polarized sources are steep-spectrum objects with a mean spectral index of -0.77 , and there is no correlation between fractional polarization and spectral index .
We also matched deep field sources to counterparts in the Faint Images of the Radio Sky at Twenty Centimeters catalogue .
Of the polarized sources , 77 \% show structure at the arc-second scale whereas only 38 \% of the sources with no detectable polarization show such structure .
The median fractional polarization is for resolved sources is 6.8 \% , while it is 4.4 \% for compact objects .
The polarized radio sources in our deep field are predominantly those sources which are resolved and show the highest degrees of fractional polarization , indicating that the lobe dominated structure may be the source of the highly polarized sources .
These resolved radio galaxies dominate the polarized source counts at P _ { 0 } = \sqrt { Q ^ { 2 } + U ^ { 2 } } < 3 mJy .