Time of Flight Mass Spectrometry is a well-known tool for the analysis of substances in a great number of scientific disciplines, including environmental sciences. The information obtained is the molecular mass to charge ratio of analytes. To reach a high accuracy and resolving power, time of flight devices need to be large so that the ions can fly for long times before they are detected. Using a reflector at the end of the flight distance allows using at least part of this distance twice, thereby increasing the resolving power. These reflectors should reflect ion packages without changing them. Furthermore, modern reflectors allow compensating differences of kinetic energy that the ions of same mass might possess. In 2016, a patent has been published proposing a reflector for time of flight mass spectrometry based electric fields with the shape of Cassinian Ovals, similarly to a Cassinian Ion Trap. In this paper we have used finite elements method simulations in order to characterize such a reflector, thereby showing how well it can fulfill its purpose regarding the previously mentioned points, i.e. not changing the ion packets and allowing for energy difference compensation.