公开(公告)号：CA2221905A1

公开(公告)日：1998-06-30

申请号：CA2221905

申请日：1997-11-24

Applicant: LUCENT TECHNOLOGIES INC

Inventor： SHOBER R ANTHONY ,  WU YOU-SUN

IPC: H04L27/22 ,  H03D1/22 ,  H03D3/00 ,  H04B1/59 ,  H04B5/00 ,  H04B7/22

Abstract: In accordance with the present invention, an RFID system has a homodyne receiver having two outputs; the in-phase or I output and the quadratur e or Q output. The modulated baskscattered signal is composed of an information signa l, modulated onto a single frequency subcarrier signal, generating a modulated subcarrier signal; this modulated subcarrier signal is then backscatter modulate d onto the incoming RF signal. To demodulate this modulated backscattered signal, the I and Q outputs are combined using an IQ combiner. This IQ combiner introduces a 90.degree. phase shift, with respect to the frequency of the subcarrier signal, onto one of the demodulator outputs and then combines the outputs of the demodulator.

公开(公告)号：CA2219099C

公开(公告)日：2002-04-16

申请号：CA2219099

申请日：1997-10-23

Applicant: LUCENT TECHNOLOGIES INC

Inventor： SWEETMAN ERIC ,  WU YOU-SUN ,  SHOBER R ANTHONY

IPC: G06K17/00 ,  G07B15/02 ,  H01P5/12 ,  H01P5/22 ,  H01Q1/22 ,  H01Q9/18 ,  H01Q13/08 ,  H01Q21/06 ,  H01Q21/08 ,  H04B1/59 ,  H04B5/00 ,  G01S13/74

Abstract: In accordance with the present invention, a general antenna system is disclosed suitable for applications in which an RFID Tag passes by an Interr ogator. We then disclose a specific antenna design that uses a single planar antenna fortransmit and a multi-element planar antenna array fo r receive. The multi-elementplanar antenna array is spaced such that each of the planar elements is four inches apart, center-to-center, thus defining a narrow 30.degree. receive beamwidth in the horizontal plane. The vertical receive bandwidth is much greater than 30.deg ree., facilitating the Interrogator receiving signals at a variety of elevations. Furthermore, a multi-way microstrip combiner is used to sum the signals received from each of the pla nar antenna. To block interference from the transmit antenna and to improve rec eivesensitivity, this multi-way microstrip combiner is s hielded using, in one embodiment, copper tape along its edges. In a specific embodiment, a four element receiv e antenna design is disclosed.

公开(公告)号：CA2221905C

公开(公告)日：2001-06-05

申请号：CA2221905

申请日：1997-11-24

Applicant: LUCENT TECHNOLOGIES INC

Inventor： WU YOU-SUN ,  SHOBER R ANTHONY

IPC: H04L27/22 ,  H03D1/22 ,  H03D3/00 ,  H04B1/59 ,  H04B5/00 ,  H04B7/22

Abstract: In accordance with the present invention, an RFID system has a homodyne receiver having two outputs; the in-phase or I output and the quadr ature or Q output. The modulated baskscattered signal is composed of an information s ignal, modulated onto a single frequency subcarrier signal, generating a modulated subcarrier signal; this modulated subcarrier signal is then backscatter modu lated onto the incoming RF signal. To demodulate this modulated backscattered signal, t he Iand Q outputs are combined using an IQ combiner. Thi s IQ combiner introduces a 90.degree. phase shift, with respect to the frequency of the subcarrier sign al, onto one of the demodulator outputs and then combines the outputs of the demodulator.

公开(公告)号：CA2219099A1

公开(公告)日：1998-06-30

申请号：CA2219099

申请日：1997-10-23

Applicant: LUCENT TECHNOLOGIES INC

Inventor： SWEETMAN ERIC ,  WU YOU-SUN ,  SHOBER R ANTHONY

IPC: G06K17/00 ,  G07B15/02 ,  H01P5/12 ,  H01P5/22 ,  H01Q1/22 ,  H01Q9/18 ,  H01Q13/08 ,  H01Q21/06 ,  H01Q21/08 ,  H04B1/59 ,  H04B5/00 ,  G01S13/74

Abstract: In accordance with the present invention, a general antenna system is disclosed suitable for applications in which an RFID Tag passes by an Interrogat or. We then disclose a specific antenna design that uses a single planar antenna for transmit and a multi-element planar antenna array for receive. The multi-element planar antenna array is spaced such that each of the planar elements is four inc hes apart, center-to-center, thus defining a narrow 30.degree. receive beamwidth in the horizontal plane. The vertical receive bandwidth is much greater than 30.degree. , facilitating the Interrogator receiving signals at a variety of elevations. Furthermore, a mu lti-way microstrip combiner is used to sum the signals received from each of the planar antenna. To block interference from the transmit antenna and to improve receive sensitivity, this multi-way microstrip combiner is shielded using, in one embodi ment, copper tape along its edges. In a specific embodiment, a four element receive an tenna design is disclosed.