Spherical antenna pattern(s) from antenna(s) arranged in a two-dimensional plane for use in RFID tags and labels

• US 5,572,226 A
• Filed: 04/11/1995
• Issued: 11/05/1996
• Est. Priority Date: 05/15/1992
• Status: Expired due to Term

• Current Assignee: Round Rock Research LLC
• Original Assignee: Micron Technology, Inc.
• Inventors: Tuttle, John R.
• Primary Examiner(s): Hajec, Donald T.
• Assistant Examiner(s): Ho, Tan
• Application Number:
  US08/422,007
• Time in Patent Office: 574 Days
• Field of Search: 343/726, 343/727, 343/728, 343/742, 343/795, 343/799, 343/867, 343/893, 343/747, 343/788, 343/853, 343/855, 342/44, 340/572, 340/505, 340/825.34
• US Class Current: 343/726
• CPC Class Codes: G01S 13/758 using a signal generator powered by the interrogation signal
• CPC Class Codes: G01S 13/765 with exchange of information between interrogator and responder
• CPC Class Codes: G01S 13/767 Responders; Transponders teaching or practice apparatus for gun-aiming or gun-laying using reflecting targets or active targets F41G3/26
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 19/073 Special arrangements for circuits, e.g. for protecting identification code in memory protection against unauthorised use of computer memory G06F12/14
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: G06K 19/07767 the first and second communication means being two different antennas types, e.g. dipole and coil type, or two antennas of the same kind but operating at different frequencies
• CPC Class Codes: H01Q 1/22 by structural association with other equipment or articles
• CPC Class Codes: H01Q 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H01Q 1/36 Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewithH01Q1/08, H01Q1/14 take precedence
• CPC Class Codes: H01Q 21/24 Combinations of antenna units polarised in different directions for transmitting or receiving circularly and elliptically polarised waves or waves linearly polarised in any direction circularly polarised patch antennas H01Q9/0428; circularly polarised horns H01Q13/0241; cross-polarised horns H01Q13/0258; polarisation converters H01Q15/242; cross-polarised rear feeds H01Q19/136; crossed polarisation dual antenna H01Q25/001
• CPC Class Codes: H01Q 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: H01Q 21/29 Combinations of different interacting antenna units for giving a desired directional characteristic H01Q25/00 takes precedence
• CPC Class Codes: H01Q 3/24 varying the orientation by switching energy from one active radiating element to another, e.g. for beam switching
• CPC Class Codes: H02J 50/23 characterised by the type of transmitting antennas, e.g. directional array antennas or Yagi antennas
• CPC Class Codes: H02J 50/27 characterised by the type of receiving antennas, e.g. rectennas
• CPC Class Codes: H02J 50/40 using two or more transmitting or receiving devices H02J50/50 takes precedence
• CPC Class Codes: H04L 2101/604 Address structures or formats
• CPC Class Codes: H04L 2101/622 Layer-2 addresses, e.g. medium access control [MAC] addresses
• CPC Class Codes: H04L 61/35 involving non-standard use of addresses for implementing network functionalities, e.g. coding subscription information within the address or functional addressing, i.e. assigning an address to a function
• CPC Class Codes: H04L 61/5038 : for local use, e.g. in LAN or USB networks, or in a controller area network [CAN]
• CPC Class Codes: H04L 61/5046 : Resolving address allocation conflicts; Testing of addresses testing when self-assigning an address H04L61/5092
• CPC Class Codes: H04L 61/5084 : Providing for device mobility network addressing or numbering for mobility support in wireless networks H04W8/26; mobile IP H04W80/04

Abstract

The present invention introduces an RFID system that comprises a two-dimensional antenna configuration having a dipole in combination with a loop antenna or a second dipole with their dipole axes at approximately a 90° angle to one another. The pattern of two dipole antennas combined with the pattern of a single loop antenna, allows the sequential combination of the patterns to represent a nearly spherical antenna pattern in three dimensions, while the antennas reside in a two-dimensional plane. The presence of multiple antennas also allows for a method to switch among the multiple antennas to find the antenna or combination of antennas that create(s) the strongest RF communication link thereby enabling more efficient transmitted power or more directional reception coverage. Improving efficiency can be further improved by taking this concept one step further by adding multiple antennas into the interrogator unit. Now the possibility exists whereby the best RF communication possible can be established between the interrogator and transceiver units by switching to the best antenna combination that would most efficiently pass an RF signal between the interrogator and the transceiver before and after which any of the antennas are now free to be used for trickle charging the chargeable battery cell(s) that reside in the transceiver unit.

Claims

1. A radio frequency (RF) transceiver system comprising first and second sending/receiving units wherein at least one of the units contains multiple antennas constructed in a planar arrangement, said planar arrangement creating a spherical electromagnetic antenna pattern, wherein said multiple antennas comprise two dipole antennas and a single loop antenna formed in said planar arrangement and oriented such that each dipole antenna axis is approximately at a 90°

angle to one another and the antenna axis of the loop antenna is approximately at a 90°

angle to the axis of at least one of said dipole antennas, thereby causing an RF signal received by said multiple antennas to create said spherical electromagnetic pattern.

2. A radio frequency identification (RFID) device comprising:

a) a sending/receiving interrogator unit; and

b) at least one tag transceiver unit having multiple antennas that are oriented such that an RF signal received by said multiple antennas creates a spherical electromagnetic pattern, wherein said multiple antennas comprise two dipole antennas and a single loop antenna formed in a planar arrangement and oriented such that each dipole antenna axis is approximately at a 90°

angle to one another and the axis of said loop antenna is approximately at a 90°

angle to the axis of at least one of said dipole antennas, thereby creating a toroidal shaped electromagnetic field centered about each said axis and resulting in said spherical electromagnetic pattern.

3. The RFID device of claim 2 wherein said transceiver unit comprises decision making circuitry, memory and a power source.

4. A tag transceiver unit in a radio frequency identification system, said tag transceiver unit comprising:

multiple antennas, said multiple antennas are oriented such that an RF signal received by said multiple antennas creates a spherical electromagnetic pattern, wherein said multiple antennas comprise two dipole antennas and a single loop antenna formed in a planar arrangement and oriented such that each dipole antenna axis is approximately at a 90°

angle to one another while the axis of said loop antenna is approximately at a 90°

angle to the axis of at least one of said dipole antennas, thereby creating a toroidal shaped electromagnetic field centered about each said axis and resulting in said spherical electromagnetic pattern.

5. The tag transceiver unit of claim 4 wherein said transceiver unit comprises decision making circuitry, memory and a power source.