  We have developed a covariant isobar model to phenomenologically explain the
four possible isospin channels of $K\Sigma$ photoproduction. To obtain a
consistent reaction amplitude, which is free from the lower-spin background
problem, we used the consistent electromagnetic and hadronic interactions
described in our previous report. We used all available experimental data,
including the recent MAMI A2 2018 data obtained for the $K^0\Sigma^+$ and
$K^0\Sigma^0$ isospin channels. By fitting the calculated observables to these
data we extract the resonance properties, including their Breit-Wigner and pole
parameters. Comparison of the extracted parameters with those listed by the
Particle Data Group yields a nice agreement. An extensive comparison of the
calculated observables with experimental data is also presented. By using the
model we investigated the effects of three different form factors used in the
hadronic vertex of each diagram. A brief discussion on the form factors is
given.
