Good day to everyone. I am doing research in the field of human body heating and I want to get confirmation of whether I have approached the modeling process correctly.

I am considering the incidence of a plane wave on a biological object in the shape of a cube with a side of 200 mm. I want to measure how deep a wave penetrates at different radiation frequencies. I have placed an "open" border around all the faces to eliminate reflection. If I make an indentation from the object, I get a strange result, as if a wave wraps around the object. Therefore, it seemed logical to use an object of infinite length, width, height, so that there would be no extraneous effects. Is this correct? Do I need to set a different type of border?