A modular passive RF apparatus includes a passive RF portal and a passive RF expansion module configured to be removably coupled with the passive RF portal. A male connector is configured to extend from a top surface of the passive RF portal, and a female connector is configured to extend from the first end wall of the passive RF expansion portal. The female connector is configured to slidingly engage the male connector in a direction parallel to the top surface of the passive RF portal in order to mechanically couple the passive RF expansion module with the passive RF portal, and the male connector is configured to prevent the female connector from being removed from the male connector in a direction perpendicular to the top surface of the passive RF portal.