A new experimental device is proposed to improve the thermal uniformity during food processing in microwave (MW) commercial ovens. The device is based on a specifically designed MW photonic crystal, acting as a homogenizer of the MW field distribution into the volume of processed food.

The project refers to the field of MW heating devices and, more particularly, to heating/cooking food placed in a MW heating device cavity. When heating food in a MW oven, two main aspects have to be considered:

a) the efficiency of the heating process, and
b) the distribution of the absorbed MW power field, i.e. the temperature uniformity in the food.

In order to achieve a uniform heating of food, it has previously been suggested to use MW stirrers or/and to place the food on a rotating plate, or the periodic modification of an inhomogeneous MW power distribution. This type of solutions is not good enough for cooking foods like, for example, “egg custard” and “meatloaf”.

Our solution for the uniform heating of the food is a homogeneous MW power distribution inside the MW heating device cavity, obtained by using a photonic crystal in the MW range. In this case, the stirrer and/or rotating food plate are not necessary.

The TRL4 experimental model, a MW homogenizer with stationary photonic crystal, has been adapted for a commercial household microwave oven and has been validated in laboratory.
The tests results confirm the improvement of the MW processing of foods.