I'm trying to simulate the temperature change due to the microwave heat source (antenna) in a specific point located in muscle tissue as it shown in the attached picture. In order to do that, I am using the multi physics option of Comsol, electromagnetic simulator with bioheat transfer physics. There are 3 tissue layers as skin, fat and muscle and the simulated point located in the muscle tissue.
I am getting different results in terms of temperature change in time when I define the biological tissue boundary as only muscle or all 3 tissue layers. For example, if I choose all three tissue layers and define as biological tissue under bioheat transfer physics and simulate the temperature, I obtain 5 Celcius degree change per minute at the point inside the muscle tissue. However, if I only choose muscle tissue, I obtain 2 Celcius degree change per minute. Which one is the correct way to simulate this problem?