Abstract: A tuning door is fabricated for a resonant cavity of a high frequency apparatus. Contact fingers are formed around the edge of a conductive plate. The plate is then fixed to a support by, for example, double sided adhesive tape. The conductive plate is part of the interior surface of the resonant cavity. The fingers may be formed in one operation, for example, by photoetching and are fully integral with the active surface to give optimum electrical conduction between them. Other types of high frequency apparatus may use contact fingers to provide electrical conduction between a movable wall and an adjacent conductive surface.