Title:
TWISTREFLECTOR ANTENNA FOR WIRELESS COMMUNICATION SYSTEM
Document Type and Number:
WIPO Patent Application WO/2000/072403
Kind Code:
A2
Abstract:
A compact lightweight antenna for receiving microwave direct line of sight wireless data signals used in services such as Local Multipoint Distribution Services (LMDS). The antenna provides for precise control over isolation of polarized signals. The antenna consists of an external parabolically shaped dome formed of a suitably resilient material such as thermoplastic. A polarizing metal grid is formed on the interior surface of the dome and serves as a transreflector for initially passing received radiation having a vertical polarization. A twist reflector disposed at a point along an axis defined by the metal grid reflects the received radiation, back in the direction of the transreflector with a different polarization. The now differently polarized energy is reflected by the parabolically shaped metal grid at a feed point located in the center of the twist plate. Operation for transmitting energy is analogous.
Inventors:
KANAMALURU SRIDHAR
WOOD KENNETH R
Application Number:
PCT/US2000/014103
Publication Date:
November 30, 2000
Filing Date:
May 23, 2000
Assignee:
TELAXIS COMM CORP (US)
International Classes:
H01Q15/12; H01Q1/42; H01Q19/06; H01Q19/195; (IPC1-7): H01Q/
Domestic Patent References:
Foreign References:
| FR1584348A | 1969-12-19 | | | |
| US4450451A | 1984-05-22 | | | |
| US5353053A | 1994-10-04 | | | |
| FR2682546A1 | 1993-04-16 | | | |
| EP0812026A2 | 1997-12-10 | | | |
Other References:
HOWARD D D AND CROSS D C: "Mirror antenna dual-band lightweight mirror design" IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, vol. AP-33, no. 3, March 1985 (1985-03), pages 286-294, XP002144517 New York, USA
KASTNER R AND MITTRA R: "A spectral-iteration technique for analyzing a corrugated-surface twist polarizer for scanning reflector antennas" IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, vol. AP-30, no. 4, July 1982 (1982-07), pages 673-676, XP002144518 New York, USA
DAHLSJ\ O: "A low sidelobe cassegrain antenna" I.E.E. CONFERENCE PUBLICATION,GB,LONDON, I.E.E, vol. NO. 105, 23 October 1973 (1973-10-23), pages 408-413, XP002131439
SILVER S: "MICROWAVE ANTENNA THEORY AND DESIGN" 1984 , PETER PEREGRINUS , LONDON, UK XP002144519 section 12.10 Rotation of polarization technique
Attorney, Agent or Firm:
Thibodeau Jr., David J. (Brook Smith & Reynolds, P.C. 530 Virginia Roa, P.O. Box 9133 Concord MA, US)
Claims:
CLAIMS What is claimed is:
| 1. |
An antenna for use in a wireless communication system, the antenna comprising: a housing having a dome shaped exterior portion thereof; a focusing transreflector consisting of a wire grid disposed along a surface of the dome and further defining an axis for the antenna, the orientation of the wire grid such that radiation having a particular polarization passes through the wire grid and radiation of other polarizations is reflected by the wire grid; and a twist reflector substantially centered along the axis and located at a distance away from the transreflector such that the twist reflector reflects received radiation back towards the focusing transreflector and imparts a polarization to the received radiation thereby reflected so that the focusing transreflector causes the reflected and polarized radiation to be focused along the axis. |
| 2. |
An antenna as in claim 1 wherein the wire grid is formed on an interior surface of the dome. |
| 3. |
An antenna as in claim 1 wherein the wire grid is formed of a plurality of parallel wires with a spacing approximately equal to onetenth of the wavelength of a carrier frequency used in the wireless communication system. |
| 4. |
An antenna as in claim 1 wherein the twist reflector further comprises: a metal plate having grooves formed in a surface facing the wire grid. |
| 5. |
An antenna as in claim 4 wherein the grooves formed in the metal plate have a depth of about onequarter of the wavelength of a carrier frequency used in the wireless communication system. |
| 6. |
An antenna as in claim 4 wherein approximately three grooves are formed in the twist plate per wavelength of a carrier frequency used in the wireless communication system. |
| 7. |
An antenna as in claim 1 wherein the twist reflector further comprises: a metalbacked dielectric layer. |
| 8. |
An antenna as in claim 1 wherein the twist reflector is additionally formed on an external face of a housing in which are enclosed a radio transceiver for receiving microwave data signals on a carrier frequency. |
| 9. |
An antenna as in claim 8 wherein the twist reflector further serves as a heat sink for electronic components of the radio transceiver. |
| 10. |
An antenna as in claim 1 wherein a feed point is disposed at the twist reflector along the axis of reception. |
| 11. |
A subscriber unit for use in a Local Multipoint Distribution Service wireless data communication system using microwave radio carrier frequencies, the subscriber unit comprising: an antenna additionally including: a housing having a dome shaped exterior portion thereof; a focusing transreflector consisting of a wire grid disposed along a surface of the dome and further defining an axis for the antenna, the orientation of the wire grid such that radiation having a particular polarization passes through the wire grid and radiation of other polarizations is reflected by the wire grid; a twist reflector substantially centered along the axis and located at a distance away from the transreflector such that the twist reflector reflects received radiation back towards the focusing transreflector and imparts a polarization to the received radiation thereby reflected so that the focusing transreflector causes the reflected and polarized radiation to be focused along the axis; a feed point disposed at the twist reflector along the axis, and arranged to couple transmit energy to the antenna and to couple receive energy from the antenna; a microwave transceiver, arranged to couple microwave modulated transmit signals and receive signals to the antenna through the feed point; and a modem, arranged to provide modulated data signals to the transceiver, and to provide demodulated data signals at an output thereof. |
| 12. |
A subscriber unit as in claim 11 wherein the wire grid is formed of a plurality of parallel wires with a spacing approximately equal to onetenth of the wavelength of the microwave carrier frequency. |
| 13. |
A subscriber unit as in claim 11 wherein the twist reflector further comprises: a metal plate having grooves formed in a surface facing the wire grid. |
| 14. |
A subscriber unit as in claim 13 wherein the grooves formed in the twist plate have a depth of about onequarter of the wavelength of the microwave carrier frequency. |
| 15. |
A subscriber unit as in claim 13 wherein approximately three grooves are formed in the twist plate per wavelength of the microwave carrier frequency. |
| 16. |
A subscriber unit as in claim 11 wherein the twist reflector further comprises a metal backed dielectric layer. |
| 17. |
A subscriber unit as in claim 11 wherein the twist reflector is additionally formed on an external face of a housing in which are enclosed a radio transceiver for receiving microwave data signals on the microwave carrier frequency. |
| 18. |
A subscriber unit as in claim 17 wherein the twist reflector further serves as a heat sink for electronic components of the transceiver. |
| 19. |
A subscriber unit as in claim 11 wherein the feed point is disposed at the twist reflector along the axis of reception. |
Description:
INTERNATIONAL SEARCH REPORT lntert nal Application No PCT/US 00/14103 C. (Continuation) DOCUMENTS CONSIDERED TO BE RELEVANT Category Citation of document, with indication, where appropriate, of the relevant passages Relevant to claim No. X KASTNER R AND MITTRA R:"A 1,2,4-6 spectral-iteration technique for analyzing a corrugated-surface twist polarizer for scanning reflector antennas" IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, vol. AP-30, no. 4, July 1982 (1982-07), pages 673-676, XP002144518 New York, USA section I: Introduction figures 1-3 X US 4 450 451 A (LA TORRE RICHARD R ET AL) 1 22 May 1984 (1984-05-22) the whole document X DAHLSJO 0:"A low sidelobe cassegrain 1 antenna" I. E. E. CONFERENCE PUBLICATION, GB, LONDON, I. E. E, vol. NO. 105, 23 October 1973 (1973-10-23), pages 408-413, XP002131439 the whole document A SILVER S :"MICROWAVE ANTENNA THEORY AND 6 DESIGN" 1984, PETER PEREGRINUS, LONDON, UK XP002144519 section 12.10 Rotation of polarization technique Y WO 99 23767 A (INTERDIGITAL TECH CORP) 11,12, 14 May 1999 (1999-05-14) 16,19 page 8, line 27-page 11, line 3; figure 3 A US 5 353 053 A (ISHIKAWA MANABU ET AL) 11 4 October 1994 (1994-10-04) column 4, line 34-49; figure 1 A FR 2 682 546 A (THOMSON COMPOSANTS 11 MICROONDES) 16 April 1993 (1993-04-16) figure1 A EP 0 812 026 A (IBM) 11 10 December 1997 (1997-12-10) column 8, line 50-column 9, line 7; figure 6 2 national application No. INTERNATIONAL SEARCH REPORT PCT/US 00/14103 Box I Observations where certain claims were found unsearchable (Continuation of item 1 of first sheet) This International Search Report has not been established in respect of certain claims under Article 17 (2) (a) for the following reasons: 1. Claims Nos.: because they relate to subject matter not required to be searched by this Authority, namely: 2. g Claims Nos. : because they relate to parts of the International Application that do not comply with the prescribed requirements to such an extent that no meaningful International Search can be carried out, specifically: 3. Claims Nos.: because they are dependent claims and are not drafted in accordance with the second and third sentences of Rule 6.4 (a). Box II Observations where unity of invention is lacking (Continuation of item 2 of first sheet) This International Searching Authority found multiple inventions in this international application, as follows: see additional sheet 1. As all required additional search fees were timely paid by the applicant, this International Search Report covers all searchable claims. 2. as ait searchable claims could be searched without effort justifying an additional fee, this Authority did not invite payment of any additional fee. 3. As only some of the required additional search fees were timely paid by the applicant, this International Search Report covers only those claims for which fees were paid, specifically claims Nos.: 4. No required additional search fees were timely paid by the applicant. Consequently, this International Search Report is restricted to the invention first mentioned in the claims; it is covered by claims Nos.: Remark on Protest g The additional search fees were accompanied by the applicant's protest. u F-xl No protest accompanied the payment of additional search fees. u FURTHER INFORMATION CONTINUED FROM PCTASA/210 This International Searching Authority found multiple (groups of) inventions in this international application, as follows: 1. Claims: 1-10 twist reflector 2. Claims : 11-19 modulation INTERNATIONAL SEARCH !----------------- ! Interr, nal Application No mformatfon on patent family members PCT/US 00/14103 PCT/US 00/14103 Patent document Publication Patent family Publication cited in search report date member (s) date FR 1584348 A 19-12-1969 NONE US 4450451 A 22-05-1984 NONE WO 9923767 A 14-05-1999 AU 7595198 A 24-05-1999 DE 970571 T 06-04-2000 EP 0970571 A 12-01-2000 ES 2139558 T 16-02-2000 US 5353053 A 04-10-1994 JP 5223638 A 31-08-1993 FR 2682546 A 16-04-1993 NONE EP 0812026 A 10-12-1997 US 5767807 A 16-06-1998 JP 10154911 A 09-06-1998
