Directional coupler collecting field for head positioning device, has directional couplers symmetrically interconnected into two branches, where output signals of branches are concentrically combined using output signal combining unit

摘要

The field has a level adjustment unit, and directional couplers (21-24, 31-34), each having an inlet and an outlet. The directional couplers are symmetrically interconnected into two branches (2, 3). Output signals of the branches are concentrically combined using an output signal combining unit (41). An impedance adjustment of each coupler is accomplishable using an amplifier (43).