  Anomalous microwave emission (AME) has been observed in numerous sky regions,
in the frequency range ~10-60 GHz. One of the most scrutinized regions is
G159.6-18.5, located within the Perseus molecular complex. In this paper we
present further observations of this region (194 hours in total over ~250
deg^2), both in intensity and in polarization. They span four frequency
channels between 10 and 20 GHz, and were gathered with QUIJOTE, a new CMB
experiment with the goal of measuring the polarization of the CMB and Galactic
foregrounds. When combined with other publicly-available intensity data, we
achieve the most precise spectrum of the AME measured to date, with 13
independent data points being dominated by this emission. The four QUIJOTE data
points provide the first independent confirmation of the downturn of the AME
spectrum at low frequencies, initially unveiled by the COSMOSOMAS experiment in
this region. We accomplish an accurate fit of these data using models based on
electric dipole emission from spinning dust grains, and also fit some of the
parameters on which these models depend.
  We also present polarization maps with an angular resolution of ~1 deg and a
sensitivity of ~25 muK/beam. From these maps, which are consistent with zero
polarization, we obtain upper limits of Pi<6.3% and <2.8% (95% C.L.)
respectively at 12 and 18 GHz, a frequency range where no AME polarization
observations have been reported to date. These constraints are compatible with
theoretical predictions of the polarization fraction from electric dipole
emission originating from spinning dust grains. At the same time, they rule out
several models based on magnetic dipole emission from dust grains ordered in a
single magnetic domain, which predict higher polarization levels. Future
QUIJOTE data in this region may allow more stringent constraints on the
polarization level of the AME.
