Choke for wireless tags
A wireless tag comprises a chip; an antenna; at least one conductive structure, the conductive structure and the chip being coupled by a common electrical connection to ground; and a filter electrically interposed along an electrical connection between the chip and the conductive structure; wherein the filter causes a reduction in amplitude of a signal passing between the conductive structure and the chip or an electrical disconnection between the conductive structure and the chip at around a prescribed frequency.
1 . A wireless tag, comprising:
a chip;
an antenna;
at least one conductive structure, the conductive structure and the chip being coupled by a common electrical connection to ground; and
a filter electrically interposed along an electrical connection between the chip and the conductive structure;
wherein the filter causes an electrical disconnection between the conductive structure and the chip at around a prescribed frequency, wherein the filter comprises an inductor and a capacitor in parallel, the inductor being formed by an arcuate single layer conductor that surrounds interdigitated fingers formed of a single layer conductor that extend in an interleaved manner inward from the arcuate conductor.
2 . The wireless tag of claim 1 , wherein the filter operates as a choke around the prescribed frequency.
3 . The wireless tag of claim 1 , wherein the prescribed frequency is about 2.4 GHz.
4 . The wireless tag of claim 1 , wherein the filter comprises an inductor and a capacitor in parallel.
5 . The wireless tag of claim 1 , wherein the filter comprises an inductor and a capacitor in parallel, each of the inductor and capacitor being implemented as a single layer.
6 . The wireless tag of claim 1 , wherein the filter comprises an inductor and a capacitor in parallel, the inductor being formed by a substantially rectangular single layer conductor that surrounds interdigitated fingers formed of a single layer conductor that extend in an interleaved manner inward from two opposing sides of the substantially rectangular single layer conductor.
7 . The wireless tag of claim 1 , wherein the filter is a narrowband filter.
8 . The wireless tag of claim 1 , wherein the conductive structure is a layer of metal.
9 . The wireless tag of claim 1 , wherein the filter is connected in series along the electrical connection between the chip and the conductive structure.
10 . The wireless tag of claim 1 , wherein the filter comprises an inductor and a capacitor in parallel and wherein the filter is arranged to have its resonance frequency at the prescribed frequency.
11 . A substrate for a wireless tag, comprising:
electrical contacts for coupling to a chip;
an antenna;
at least one conductive structure, the conductive structure and at least one of the electrical contacts for coupling to the chip being coupled by a common electrical connection to ground; and
a filter electrically interposed along an electrical connection between the at least one of the electrical contacts for coupling to the chip and the conductive structure;
wherein the filter causes an electrical disconnection between the conductive structure and the chip at around a prescribed frequency, wherein the filter comprises an inductor and a capacitor in parallel, the inductor being formed by an arcuate single layer conductor that surrounds interdigitated fingers formed of a single layer conductor that extend in an interleaved manner inward from the arcuate conductor.
12 . The substrate for a wireless tag of claim 11 , wherein the filter operates as a choke around the prescribed frequency.
13 . The substrate for a wireless tag of claim 11 , wherein the prescribed frequency is about 2.4 GHz.
14 . The substrate for a wireless tag of claim 11 , wherein the filter comprises an inductor and a capacitor in parallel.
15 . The substrate for a wireless tag of claim 11 , wherein the filter comprises an inductor and a capacitor in parallel, each of the inductor and capacitor being implemented as a single layer.
16 . The substrate for a wireless tag of claim 11 , wherein the filter comprises an inductor and a capacitor in parallel, the inductor being formed by a substantially rectangular single layer conductor that surrounds interdigitated fingers formed of a single layer conductor that extend in an interleaved manner inward from two opposing sides of the substantially rectangular single layer conductor.
17 . The substrate for a wireless tag of claim 11 , wherein the filter is a narrowband filter.
18 . The substrate for a wireless tag of claim 11 , wherein the conductive structure is a layer of metal.
19 . The substrate for a wireless tag of claim 11 , wherein the filter is connected in series along the electrical connection between the at least one of the electrical contacts for coupling to the chip and the conductive structure.
20 . The substrate for a wireless tag of claim 11 , wherein the filter comprises an inductor and a capacitor in parallel and wherein the filter is arranged to have its resonance frequency at the prescribed frequency.
21 . A wireless tag, comprising:
a chip;
an antenna;
at least one conductive structure, the conductive structure and the chip being coupled by a common electrical connection to ground; and
a choke electrically interposed along an electrical connection between the chip and the conductive structure;
wherein the choke acts as a filter to cause a reduction in amplitude of a signal passing between the conductive structure and the chip at around a prescribed frequency, wherein the filter comprises an inductor and a capacitor in parallel, the inductor being formed by an arcuate single layer conductor that surrounds interdigitated fingers formed of a single layer conductor that extend in an interleaved manner inward from the arcuate conductor.
22 . The wireless tag of claim 21 , wherein the prescribed frequency is the resonance frequency of the choke.
23 . The wireless tag of claim 21 , wherein the choke comprises an inductor and a capacitor in parallel, each of the inductor and capacitor being implemented as a single layer.