Methods and apparatus for shielding an object from relative high electromagnetic radio frequencies while allowing airflow to pass to and from the object are disclosed. According to one aspect of the present invention, a shield arrangement that shields a chassis includes at least a first plane and a second plane. The first plane has a thickness and defines a first plurality of openings that include a first opening and a second opening that are separated by at least a distance that is a function of the thickness. The second plane defines at least a third opening, and is approximately parallel to the first plane. The second plane is spaced apart from the first plane by a spacing that is a function of at least the thickness.