An appliance, such as an oven, includes a housing having an internal compartment and an RF antenna. At least a portion of the housing comprises an electrically conductive portion. The antenna includes an active component and a connection to the electrically conductive portion, which serves as a ground plane of the antenna. The housing may include a door assembly having a window that includes the electrically conductive portion in the form of a transparent conductive layer. The door assembly may be detachable and the connection to the antenna may be made by way of capacitive coupling. In an alternative arrangement, the housing includes a light fixture for illuminating the internal compartment, wherein the active component of the antenna is disposed in the light fixture.