Polarization diverse antenna for portable communication devices

• US 6,031,503 A
• Filed: 02/20/1997
• Issued: 02/29/2000
• Est. Priority Date: 02/20/1997
• Status: Expired due to Fees

• Current Assignee: Systemonic AG (Koninklijke Philips N.V.)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Beltran, Fernando, Donaldson, Stephen R., Van Doren, Arnold E., Preiss, Joseph A. II, McElroy, Terry L.
• Primary Examiner(s): LE, HOANGANH T
• Application Number:
  US08/803,478
• Time in Patent Office: 1,104 Days
• Field of Search: 343/770, 343/767, 343/702, 343/700 MS, 343/725, 343/795, 343/794, 343/727, 343/729, 343/730, 343/846
• US Class Current: 343/770
• CPC Class Codes: G06K 19/07743 External electrical contacts
• CPC Class Codes: H01Q 1/2275 associated to expansion card or bus, e.g. in PCMCIA, PC cards, Wireless USB
• CPC Class Codes: H01Q 13/10 Resonant slot antennas
• CPC Class Codes: H01Q 13/16 Folded slot antennas
• 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: H04B 1/38 Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
• CPC Class Codes: H04B 7/0802 using antenna selection H04B7/0868 takes precedence; antenna beam directivity switching H01Q3/24

Abstract

A communications card having an antenna assembly providing polarization diversity for use with a portable computer is provided. The antenna assembly comprises two folded antennas, which may be dipoles or slot radiators, that are disposed orthogonally to one another to provide polarization diversity. Signals are carried to and from the antenna by microstrip feed lines. The microstrip lines are placed off center along each antenna slot to establish an acceptable impedance match for the antenna. The feed lines are coupled to the communications card by way of coaxial cables. The antenna assembly is coupled with the communications card in a hinged arrangement thus allowing for spatial redirection of the antenna, if desired.

Claims

1. A communications card for transmission and reception of microwave signals with an associated portable computer, the communications card comprising:

(A) a transceiver portion including receiver and transmitter electronics for communication of said signals to and from said computer;

(B) a polarization diverse antenna assembly having;

1) a first antenna and an orthogonally-disposed second antenna with each antenna being substantially omnidirectional about a first axis;

2) a single metal sheet adhered to a plastic substrate, said metal sheet comprising a ground plane conductor, and the first and second antennas being first and second slot radiators formed in said metal sheet, said slot radiators being unobstructed on both sides so that signals may be radiated and received from both sides of said ground plane conductor;

(C) a card body sized for insertion into a card slot in the portable computer, said card body having an RF section including said transceiver portion, and a digital electronics portion which provides a connection to the computer, and said antenna assembly being attached to said RF section of said card body in a hinge arrangement, whereby the radiation pattern of said antenna assembly is adjustable for obtaining maximum signal quality by rotation of said antenna assembly about said hinge arrangement;

(D) coupling means disposed between said transceiver portion and said antenna assembly for communicating signals between said transceiver portion and said antenna assembly.

2. The communications card of claim 1 wherein

said transceiver portion includes a switch for selecting between signals received from said first antenna and said second antenna based upon the signal-to-noise ratio of the signal so produced by each of said first and second antennas.

3. The communications card of claim 1 wherein

said coupling means includes a first microstrip feed line coupled at one end to said transceiver portion and connected at an other end across said first slot radiator, and a second microstrip feed line coupled at one end to said transceiver portion and connected at an other end across said second slot radiator.

4. The communications card of claim 3 wherein

said first and said second microstrip feed lines are offset from a center of each of said first and second slot radiators, respectively, by a predetermined amount to set the impedance characteristic of said antenna assembly.

5. The communications card of claim 3 wherein

said coupling means includes a first and second coaxial cable connected from said first and second microstrip feed lines, respectively, of said antenna assembly, to said transceiver portion.

6. The communications card of claim 5 wherein:

said first coaxial cable has an outer conductor connected to a first ground pad disposed on said ground plane conductor, and a center conductor connected to said one end of said first microstrip feed line, and said second coaxial cable has an outer conductor connected to a second ground pad disposed on said ground plane conductor, and a center conductor connected to said one end of said second microstrip feed line.

7. The communications card of claim 5 wherein

said first and second coaxial cables are housed within said hinge arrangement.

8. The communications card of claim 1 wherein

said antenna assembly is encapsulated in a plastic housing, said plastic housing being attached to said RF section of said card body.

9. The communications card of claim 8 wherein

said plastic housing is sized to conform to said card body in such a manner that it can be folded flush against said card body for storage when not in use.

10. The communications card of claim 9 wherein

said ground plane conductor is sized to fit within said plastic housing and said first and second slot radiators are C-shaped, folded slot radiators dimensioned to conform to said ground plane conductor.

11. The communications card of claim 10 wherein

said computer is a PCMCIA portable computer and said card body is dimensioned to conform to said card slot associated with said portable computer.

12. A polarization diverse antenna assembly for use with a computer device, for the transmission and reception of microwave communications with a transceiver associated with the computer, the antenna assembly comprising:

(A) a first antenna and an orthogonally-disposed second antenna with each antenna being substantially omnidirectional about a first axis;

(B) a single metal sheet adhered to a plastic substrate, said metal sheet comprising a ground plane conductor, and the first and second antennas being first and second slot radiators formed in said metal sheet, said slot radiators being unobstructed on both sides so that signals may be radiated and received from both sides of said ground plane conductor;

(C) coupling means disposed between said transceiver and said first and second antennas for communicating signals between said transceiver and said first and second antennas; and

(D) hinge arrangement connecting said antenna assembly to said transceiver portion in such manner that the spatial direction of said antenna assembly is adjustable by rotation of said antenna assembly about said hinge arrangement for obtaining maximum signal quality.

13. The antenna assembly of claim 12 wherein said first and second slot radiators are C-shaped, folded slot radiators dimensioned to conform to said ground plane conductor.

14. The antenna assembly of claim 12 wherein

said coupling means includes a first microstrip feed line coupled at one end to said transceiver portion and connected at an other end across said first slot radiator, and a second microstrip feed line coupled at one end to said transceiver portion and connected at an other end across said second slot radiator, and said first and second microstrip feed lines are offset from a center of each of said first and second slot radiators, respectively, by a predetermined amount to set the impedance characteristics of said antenna assembly.

15. The antenna assembly of claim 14 further comprising

a card body sized for insertion in to a card slot in said computer device, said card body having an RF section including said transceiver, and a digital electronics portion which provides a connection to said associated computer device, and said ground plane conductor including said first and second antennas is encapsulated in a plastic housing, said plastic housing being attached to said RF section of said card body.