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US 7,412,172 B2Granted
Impedance matching circuit with simultaneous shielding of parasitic effects for transceiver modules
AssigneeInternational Business Machines Corporation
InventorsDaniel M. Kuchta, Mark B. Ritter, Albert E. Ruehli, Christian Schuster
Life of this patent
Estimating the term…
Abstract
An RF device includes a signal layer disposed over a ground plane having radio frequency (RF) transmission lines configured and dimensioned to provide impedance matching along the RF lines. A shield is formed as a part of the RF lines and disposed below the RF choke of a DC current supply to form an intermediate capacitance between the choke and the shield to control parasitic effects.
Claims12
A radio frequency device, comprising:
- a signal layer having radio frequency (RF) transmission lines disposed over a ground plane, the RF lines configured and dimensioned to provide impedance matching along the RF lines;
- and
- a shield formed as a part of the RF lines and disposed below an RF choke of a DC current supply to form an intermediate capacitance between the choke and the shield to control parasitic effects wherein the intermediate capacitance and impedances of the parasitic effects form a circuit which controls the parasitic effects;
- wherein a balance between the intermediate capacitance versus the parasitic effects is achieved to provide a flat or peaked transmission response over a selected frequency range, and the balance includes:
- Cs/Cg≧Rl/Rm where Cs is the intermediate capacitance, Cg is a parasitic capacitance between the choke and the ground plane, Rm is a matching resistance and Rl is the load.
2 more elements
An optical transceiver, comprising:
- a substrate having a signal layer formed thereon, the signal layer having radio frequency (RF) transmission lines disposed over a wound plane, the RF lines configured and dimensioned to provide impedance matching along the RF lines, the RF lines having a portion forming a shield;
- the shield being disposed below an RF choke of a DC current supply to form an intermediate capacitance between the choke and the shield to control parasitic effects wherein a balance between the intermediate capacitance versus the parasitic effects is achieved to provide a flat or peaked transmission response over a selected frequency range, the balance includes:
- Cs/Cg≧Rl/Rm where Cs is the intermediate capacitance, Cg is a parasitic capacitance between the choke and the ground plane, Rm is a matching resistance and Rl is the load;
- and
- a laser modulated in accordance with RF signals transmitted by the RF lines.
2 more elements
Dependencies are inferred from the claim text.