The radiant patio heaters are using a heat reflector, not deflector. Think optics. Gas radiant heaters attempt to convert as much of the heat released by combustion into radiant heat. This minimizes heat lost to convection and redirects it to the targeted zone. The reflective heat shield helps to reflect heat that is escaping upwards.
There was some discussion about radiant burners on the Stoves list last month. It stalled because of some false assumptions and unnecessary snittyness, but in the process some interesting patents were found that could be applied to a wood
or biomass burning stove. This is one I think you might find interesting:
You could make some adjustments to the design to suit your application.