PURPOSE:To realize both a small size and high performance by using the central conductor plate for the strip line terminal and then providing the tab to the conductor plate to use it for the load capacity. CONSTITUTION:Ferrite plates 13 (13a, 13b) and central conductors 14 (14a-14c) are held between permanent magnet 8 and soft magnetic substance plate 16. Magnet 8 functions the upper cover directly, and plate 16 doubles the earth conductor. Thus the capacity is caused between magnet 8 and plate 16. The tabs 21 (21a, 21b) are installed to central earth plate 14 to control the capacity. As a result, the optimum load capacity is realized to secure the high performance as well as omit the external capacity. Furthermore, the whole structure can be unified into a compact form. Both the unevenness and the shape are optional for tabs 21 according to each earth conductor.