A method and apparatus for creating uniform heating of an microwave
absorptive target. A microwave housing has a longitudinal axis and
propagates a waveguide mode at an operating frequency. The target is
located in an axial cross-sectional area relative to the longitudinal
axis. First layer conductive strips are layered proximal to an inner wall
of the microwave housing, substantially parallel to the longitudinal axis
and being separated from an adjacent first layer conductive strip by a
respective first layer gap, the inner wall acting as a ground plane.
Second layer conductive strips are layered proximal to the first layer of
conductive strips, parallel to the longitudinal axis and being separated
from an adjacent second layer conductive strip by a respective second
layer gap. Each first layer gap is centered under a respective second
layer conductive strip and each second layer gap is centered over a
conductive layer.