  Microwave emission of solar flares is formed primarily by incoherent
gyrosynchrotron radiation generated by accelerated electrons in coronal
magnetic loops. The resulting emission depends on many factors, including
pitch-angle distribution of the emitting electrons and the source geometry. In
this work, we perform systematic simulations of solar microwave emission using
recently developed tools (GS Simulator and fast gyrosynchrotron codes) capable
of simulating maps of radio brightness and polarization as well as spatially
resolved emission spectra. A 3D model of a symmetric dipole magnetic loop is
used. We compare the emission from isotropic and anisotropic (of loss-cone
type) electron distributions. We also investigate effects caused by
inhomogeneous distribution of the emitting particles along the loop. It is
found that effect of the adopted moderate electron anisotropy is the most
pronounced near the footpoints and it also depends strongly on the loop
orientation. Concentration of the emitting particles at the loop top results in
a corresponding spatial shift of the radio brightness peak, thus reducing
effects of the anisotropy. The high-frequency (around 50 GHz) emission spectral
index is specified mainly by the energy spectrum of the emitting electrons;
however, at intermediate frequencies (around 10-20 GHz), the spectrum shape is
strongly dependent on the electron anisotropy, spatial distribution, and
magnetic field nonuniformity. The implications of the obtained results for the
diagnostics of the energetic electrons in solar flares are discussed.
