A reflective elliptical cavity is analysed to couple a cylindrical burner with a receiver made of three arrays of thermophotovoltaic cells. The advantage of the elliptical shape is that burner and receiver can be placed in the two foci of the ellipse; while in the circular cavity they should be both placed in the centre. The elliptical cavity is studied as component for a thermo-electric cogenerator of thermophotovoltaic type, considering practical requirements and realisation constraints. Ray-tracing analyses examine received power, collection efficiency and irradiance distribution; in particular the uniformity of the light focused on the receiver is very important to maximise the thermophotovoltaic conversion. The research compares the elliptical reflective cavity with the circular cavity, for various distances between burner and receiver. Increasing diameters of the burner are considered in the elliptical cavity, choosing the best solution. An ideal-diffusion reflector is considered to realise the cavity walls, instead of a specular-reflection material.