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US 6,643,501 B1Granted
Flexible ferrite gasket for receiver second image protection
AssigneeSierra Wireless, Inc.
InventorsTrent McKeen, Dominque Kwong
Life of this patent
Estimating the term…
Abstract
In a superheterodyne receiver, energy can bypass a filter by magnetically coupling to a metallic radio frequency shield. This is especially a problem with small form factor devices in which the metallic radio frequency shield is positioned close to the filter. By using a ferrite-embedded element positioned between the filter and the RF shield, some of the undesired harmonics produced by the mixer can be dissipated into heat.
Claims18
An apparatus comprising:
- an image energy filter:
- a mixer operably connected to an output of the image filter and to a local oscillator signal;
- a metal radio frequency (RF) shield positioned over the filter;
- and
- a ferrite-embedded element placed between the filter and the metal RF shield, the ferrite-embedded element adapted to reduce the unwanted energy that would otherwise bypass the filter via the metal RF shield.
2 more elements
An apparatus comprising:
- an image energy filter having matching circuits including inductors;
- a mixer operably connected to an output of the image energy filter and to a local oscillator signal;
- a metal radio frequency shield positioned over the filter;
- and
- a ferrite-embedded element placed between the filter and the metal RF shield, the ferrite-embedded element adapted to dissipate energy radiated by the inductors.
2 more elements
Dependencies are inferred from the claim text.