  SCUBA-2 is the next-generation replacement for SCUBA (Sub-millimetre Common
User Bolometer Array) on the James Clerk Maxwell Telescope. Operating at 450
and 850 microns, SCUBA-2 fills the focal plane of the telescope with
fully-sampled, monolithic bolometer arrays. Each SCUBA-2 pixel uses a
quarter-wave slab of silicon with an implanted resistive layer and backshort as
an absorber and a superconducting transition edge sensor as a thermometer. In
order to verify and optimize the pixel design, we have investigated the
electromagnetic behaviour of the detectors, using both a simple
transmission-line model and Ansoft HFSS, a finite-element electromagnetic
simulator. We used the transmission line model to fit transmission measurements
of doped wafers and determined the correct implant dose for the absorbing
layer. The more detailed HFSS modelling yielded some unexpected results which
led us to modify the pixel design. We also verified that the detectors suffered
little loss of sensitivity for off-axis angles up to about 30 degrees.
