Microstrip Ice Detectors
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lines are now being used to detect the presence of ice on aircraft wings
in experiments . Their thinness allows installation at the surface of
the airfoil where the ice accumulates without significantly affecting
the airfoil shape. Sensor spots are areas of microstrip that are exposed
to the environment and depend on a change in local capacitance due to
the presence of ice or water. The spots are spaced at open circuit points
every half wavelength (about 4 inches for the substrate in use). A 1
GHz signal is fed into the system and the return loss phase and magnitude
is used determine when to activate de-icing equipment. A microprocessor
corrects the I and Q components to maintain the waveshape along the
transmission line so that a constant reference is maintained. This work
is being done at the Johnson Space Center in Texas.