  The convection plays a very important role in heat transfer when MEMS work
under air environment. However, traditional measurements of convection heat
transfer coefficient require the knowledge of thermal conductivity, which makes
measurements complex. In this work, a modified steady state "hot wire" (MSSHW)
method is proposed, which can measure the heat transfer coefficient of
microwires' convection without the knowledge of thermal conductivity. To verify
MSSHW method, the convection heat transfer coefficient of platinum microwires
was measured in the atmosphere, whose value is in good agreement with values by
both traditional measurement methods and empirical equations. Then, the
convection heat transfer coefficient of microwires with different materials and
diameters were measured by MSSHW. It is found that the convection heat transfer
coefficient of microwire is not sensitive on materials, while it increases from
86 W/(m$^2$K) to 427 W/(m$^2$K) with the diameter of microwires decreasing from
120 ${\mu}$m to 20 ${\mu}$m. Without knowing thermal conductivity of
microwires, the MSSHW method provides a more convenient way to measure the
convective effect.
