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Article: A planar impedance transformer.
- Article from:
- Microwave Journal
- Article date:
- October 1, 1998
- Author:
CopyrightCOPYRIGHT 1998 Horizon House Publications, Inc. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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Impedance transformers with wire windings coiled on a toroidal ferrite bead are used at RFs up to approximately 3 GHz. Because of their small size, such devices are favored when space requirements are tight. On the other hand, the winding of coils on a bead requires the use of expensive dedicated machinery for series production. Moreover, each transformer must be attached to or housed inside an individual case for automatic placement on PCBs. These two operations - let alone the raw wire, bead and housing - require as much as a few square centimeters of PCB space. This amount of space can make the circuit designer question whether some planar component could be used instead ...