Protection system for radio frequency communications
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
G08B-013/14
H04K-001/02
G06K-019/06
G06K-019/073
H01Q-007/00
H01Q-001/22
출원번호
US-0663860
(2012-10-30)
등록번호
US-9129200
(2015-09-08)
발명자
/ 주소
Lavedas, Thomas G.
출원인 / 주소
Raytheon Corporation
대리인 / 주소
Daly, Crowley, Molford & Durkee, LLP
인용정보
피인용 횟수 :
0인용 특허 :
53
초록
A system for protecting radio frequency (RF) communications and related techniques includes generating masking signals at an RF device such as a radio frequency identification (RFID) card.
대표청구항▼
1. A radio frequency identification (RFID) card for use with an RFID reader, the RFID card comprising: a substrate;an RFID antenna disposed on said substrate, said RFID antenna configured on said substrate to be responsive to RFID reader signals provided thereto along a first direction;a jamming sys
1. A radio frequency identification (RFID) card for use with an RFID reader, the RFID card comprising: a substrate;an RFID antenna disposed on said substrate, said RFID antenna configured on said substrate to be responsive to RFID reader signals provided thereto along a first direction;a jamming system coupled to said substrate and configured to emit masking signals in directions other than the first direction so as to not interfere with communications between said RFID antenna and the RFID reader, wherein the jamming system comprises a cross-fed antenna, the cross-fed antenna aligned with the RFID antenna such that signals emitted from the cross-fed antenna are not received by the RFID antenna; anda secondary antenna disposed about the cross-fed antenna wherein said secondary antenna is configured as a pick-up loop to provide a sample of an interrogation signal from an RFID reader, wherein the secondary antenna is positioned with respect to the cross-fed antenna such that the secondary antenna is isolated from an interference signal provided to the cross-fed antenna;wherein the secondary antenna is configured to activate a jammer signal only when the secondary antenna is in the near vicinity of an interrogating reader and wherein when the secondary antenna does not activate a jammer signal, the jamming system conserves power and limits an amount of information an eavesdropper can gain from long term data collection of the jammer signal. 2. The RFID card of claim 1 wherein said cross-fed antenna comprises: a pair of loops; anda common feed point. 3. The RFID card of claim 1 wherein said jamming system comprises: a cross-fed antenna comprising a pair of loops fed from a common feed point; anda transmitting device configured to provide a jamming signal, said transmitting device having an RF output port coupled to a first feed point of said cross-fed antenna such that a first feed signal provided thereto generates electrical currents in a first pair of loops wherein the electrical currents travel in opposite sense through each loop and having RF output port coupled to a second feed signal provided thereto generates at 90 degrees phase relative to the first electrical currents in a second pair of loops wherein the electrical currents travel in opposite sense through each loop so as together to form a radiation pattern having a donut shape. 4. The RFID card of darn 3 wherein a single conductor forms adjacent legs of the first two loops used in said cross-fed antenna and a second single conductor forms adjacent legs of the second two loops to provide a single loop having two common centrally located feeds. 5. The RFID card of claim 4 wherein each of said pair of loops are provided having one of: a square shape;a rectangular shape;a crossed rectangle shape;a circular shape;an oval shape;an octagonal shape;an hexagonal shape; andan diamond shape. 6. The RFID card of claim 4 wherein each loop is provided having at least half-plane symmetry around a feed leg, such that each half of the structure is equal in size and has a common side. 7. The RFID card of claim 1 wherein said jamming system further comprises: a transmitting device coupled to the cross-fed antenna. 8. The RFID card of claim 7 wherein said transmitting device comprises: a noise source;a power amplifier; anda power source. 9. The RFID card of claim 1 wherein the sample of the interrogation signal from the RFID reader provides a reference that is processed for use as a local oscillator signal to implement coherent spoofing. 10. The RFID card of claim 9 wherein the interfering signal provided by said jamming system is structured like that of one or more RFID cards in the immediate vicinity of the card being protected. 11. The RFID card of claim 10 wherein the added signals appear as code collisions to the eavesdropping receiver making it nearly impossible to distinguish the interfering signals from the real RFID responses. 12. An RFID system comprising: an RFID reader;one or more RFID cards, each RFID card comprising: a substrate:an RFID antenna disposed on substrate, said RFID antenna configured on said substrate to be responsive to RFID reader signals provided thereto along a first direction; anda secondary antenna configured as a pick-up loop to provide a sample of an interrogation signal from an RFID reader, wherein the secondary antenna is configured to activate a jammer signal only when the secondary antenna is in the near vicinity of an interrogating reader;wherein at least some of the RFID cards further comprise an integrated jamming system, the jamming system comprising:(a) a cross-fed antenna aligned with the RFID antenna such that signals emitted from the cross-fed antenna are not received by the RFID antenna, wherein the secondary antenna is disposed about the cross-fed antenna and positioned with respect to the cross-fed antenna such that the secondary antenna is isolated from an interference signal provided to the cross-fed antenna; and(b) a transmitting system coupled to the cross-fed antenna;wherein the cross-fed antenna and transmitting system are configured to generate an antenna pattern having a null in the direction of the RFID reader, the null configured to enable communication between the RFID reader and the respective RFID card having the integrated jamming system, and to generate a jamming signal in other directions about the null direction, such that the jamming system does not interfere with communication between the RFID reader and the respective RFID card having the integrated jamming system; andwherein when the secondary antenna dose not activate a jamming signal, the integrated jamming system conserves power and limits an amount of information an eavesdropper can gain from long term data collection of the jammer signal. 13. The RFID system of claim 12 wherein said cross-fed antenna is provided as a loop antenna having two isolated inputs, said loop antenna configured such that in response to being fed with signals that are in phase quadrature, said cross-fed antenna generates an omni-directional radiation pattern. 14. The RFID system of claim 13 wherein each of the one or more RFID cards comprises an RFID loop antenna and wherein said cross-fed antenna is disposed relative said an RFID loop antenna such that said RFID loop antenna is isolated from said cross-fed antenna. 15. An RFID method comprising: (a) providing an RFID card comprising: (a-1) a substrate;(a-2) an RFID antenna disposed on substrate, said RFID antenna configured on said substrate to be responsive to RFID reader signal provided thereto along a first direction;(a-3) a jamming system coupled to said substrate and configured to emit masking signals in directions other than the first direction so as not to interfere with communications between said RFID antenna and the RFID reader, wherein the jamming system comprises a cross-fed antenna, the cross-fed antenna aligned with the RFID antenna such that signals emitted from the cross-fed antenna are not received by the RFID antenna; and(a-4)a secondary antenna disposed about the cross-fed antenna wherein said secondary antenna is configured as a pick-up loop to provide a sample of an interrogation signal from an RFID reader, wherein the secondary antenna is positioned with respect to the cross-fed antenna such that the secondary antenna is isolated from an interference signal provided to the cross-fed antenna;(a-6)wherein the secondary antenna is configured to activate a jammer signal only when the secondary antenna is in the near vicinity of an interrogating reader and wherein when the secondary antenna does not activate a jammer signal, the jamming system conserves power and limits an amount of information an eavesdropper can gain from long term data collection of the jammer signal;(b) emitting a response signal from the radio frequency identification (RFID) card along a first direction; and(c) emitting a masking signal from the RFID card at the same time the response signal is emitted, wherein the masking signal is emitted in a direction other than the first direction so as not to interfere with communications of the response signal to a receiving device. 16. The method claim of 15, wherein the masking signal is generated based upon the response signal. 17. The method of claim 16, wherein the masking signal appears as noise to mask the response signal. 18. The method of claim 16, further comprising determining if two interrogator signals are received at the RFID card within a predetermined period of time and generating a masking signal in response thereto. 19. The method of claim 15, wherein the masking signal is generated based upon another response signal from at least one other antenna in the area about the responder. 20. An antenna comprising: an RFID antenna portion, the RFID antenna configured to be responsive to RFID reader signals provided thereto along a direction;a jamming portion configured to emit masking signals in directions other than the first direction so as not to interfere with communications between the RFID antenna and an RFID reader, the jamming portion comprising: a masking antenna portion configured to broadcast the masking signals, said masking antenna portion comprising a cross-fed antenna having a first loop and a second loop wherein the first and second loops are fed from a common feed point, wherein the cross-fed antenna is aligned with the RFID antenna such that signals emitted from the cross-fed antenna are not received by the RFID antenna;a secondary antenna disposed about the cross-fed antenna wherein said secondary antenna is configured as a pick-up loop to provide a sample of an interrogation signal from an RFID reader, wherein the secondary antenna is positioned with respect to the cross-fed antenna such that the secondary antenna is isolated from an interference signal provided to the cross-fed antenna, wherein the secondary antenna is configured to activate a jammer signal only when the secondary antenna is in the near vicinity of an interrogating reader and wherein when the secondary antenna does not activate a jammer signal, the jamming system conserves power and limits an amount of information an eavesdropper can gain from long term data collection of the jammer signal; anda reader loop antenna portion configured to receive a response signal from a responder and decoupled from the masking antenna portion;wherein the antenna is configured to permit the masking antenna to broadcast the masking signal at the same time that the reader loop antenna is receiving a response signal. 21. The system of claim 20, wherein when a feed signal provided to a feed point of said cross-fed antenna excites electrical current in a first pair of loops wherein the electrical currents travel in opposite sense through each loop and having an RF output port coupled to a second feed signal provided thereto generates at 90 degrees phase relative to the first electrical currents in a second pair of loops wherein the electrical currents travel in opposite sense through each respective loop so as together to form a radiation pattern having a donut shape. 22. The system of claim 21 wherein each respective pair of loops is a substantially identical pair of loops fed from the common feed point. 23. The antenna of claim 20, wherein said cross-fed antenna portion and said reader loop antenna portion are disposed in substantially parallel planes. 24. A method of transferring information between a radio frequency identification (RFID) card and an RFID reader, the method comprising: providing an RFID card comprising: a substrate;an RFID antenna disposed on substrate, said RFID antenna configured on said substrate to be responsive to RFID reader signal provided thereto along a first direction;a jamming system coupled to said substrate and configured to emit masking signals in directions other than the first direction so as to not interfere with communications between said RFID antenna and the RFID reader, wherein the jamming system comprises a cross-fed antenna, the cross-fed antenna aligned with the RFID antenna such that signals emitted from the cross-fed antenna are not received by the RFID antenna; anda secondary antenna disposed about the cross-fed antenna wherein said secondary antenna is configured as a pick-up loop to provide a sample of an interrogation signal from an RFID reader, wherein the secondary antenna is positioned with respect to the cross-fed antenna such that the secondary antenna is isolated from an interference signal provided to the cross-fed antenna, wherein the secondary antenna is configured to activate a jammer signal only when the secondary antenna is in the near vicinity of an interrogating reader and wherein when the secondary antenna does not activate a jammer signal, the jamming system conserves power and limits an amount of information an eavesdropper can gain from long term data collection of the jammer signal;in response to an interrogation signal provided by the RFID reader, the interrogation signal oriented along the first direction: generating a masking signal wherein the masking signal originates on or proximate the RFID card, the masking signal oriented in a second direction, the second direction being a direction other than the first direction so as not to interfere with communications between the RFID reader and the RFID card; andgenerating a response signal in the RFID card and providing the response signal to the RFID reader; andproviding the response signal from the RFID card to the RFID reader. 25. The method of claim 24, wherein the masking signal originates from one of: the RFID card having a jamming antenna with an antenna pattern null aligned with the RFID reader; andcarrier for a portable electronic device, wherein said carrier comprises a jamming antenna, wherein said carrier is disposed proximate the RFID card and is aligned with the RFID card such that an antenna pattern null of the jamming antenna is aligned with the RFID reader. 26. The method of claim 24, wherein generating a masking signal comprises generating the masking signal based upon the response signal. 27. The method of claim 24, wherein generating a masking signal comprises generating the masking signal based upon another response signal from at least one other antenna in the area about the antenna. 28. A portable jamming system for use with a radio frequency (RF) device, the portable jamming system comprising: a frame configured to be coupled to an RFID device;a cross-fed antenna coupled to the frame, the cross-fed antenna comprising: a first loop;a second loop electrically coupled to the first loop; anda common feed point, wherein a current supplied to the common feed point causes the cross-fed antenna to generate an antenna radiation pattern having a donut shape wherein a null portion of the antenna radiation pattern is directed toward the RFID reader when the RFID card is aligned with the RFID reader, the antenna radiation pattern configured to interfere with communication with the RFID reader in areas outside of its null portion and to not interfere with communications with the RFID reader within its null portion;a transmitter coupled to said frame and said cross-fed antenna;a reader loop antenna configured to coupled a signal from an interrogator;a spoofing system coupled to the cross-fed antenna and the reader loop antenna; anda spoofing system coupled to the cross-fed antenna and the reader loop antenna, the spoofing system comprising: a receiver having an input coupled to receive a message signal from said reader loop antenna;a controller coupled to receive a message signal from the receiver and to generate an interference signal at an output therefore; anda modulator having a first input coupled to receive a carrier signal from the receiver, having a second input coupled to the output of the controller and having an output signal coupled to the cross-fed antenna.
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