MICROSTRIP ANTENNA FOR RFID DEVICE
First Claim
1. A radio frequency identification transponder comprising:
- a microstrip patch antenna;
a first feed and a second feed, each feed being coupled with an edge of the microstrip patch antenna, and the first feed being approximately 180 degrees out of phase with the second feed; and
a matching circuit coupling the first and second feeds with an integrated circuit.
1 Assignment
0 Petitions
Accused Products
Abstract
Microstrip patch antenna (46), feed structure (48), and matching circuit (50) designs for an RFID tag (10). A balanced feed design using balanced feeds coupled by a shorting stub (56) to create a virtual short between the two feeds so as to eliminate the need for physically connecting substrate to the ground plane. A dual feed structure design using a four-terminal IC can be connected to two antennas (46a,46b) resonating at different frequencies so as to provide directional and polarization diversity. A combined near/field-far/field design using a microstrip antenna providing electromagnetic coupling for far-field operation, and a looping matching circuit providing inductive coupling for near-field operation. A dual-antenna design using first and second microstrip antennas providing directional diversity when affixed to a cylindrical or conical object, and a protective superstrate (66). An annual antenna (46c) design for application to the top of a metal cylinder around a stem.
-
Citations
51 Claims
-
1. A radio frequency identification transponder comprising:
-
a microstrip patch antenna;
a first feed and a second feed, each feed being coupled with an edge of the microstrip patch antenna, and the first feed being approximately 180 degrees out of phase with the second feed; and
a matching circuit coupling the first and second feeds with an integrated circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. In a radio frequency identification transponder for physical association with an object and for storing and communicating data regarding the object, the radio frequency identification transponder having a microstrip patch antenna and an integrated circuit, the improvement comprising:
-
a first feed and a second feed, each feed being coupled with an edge of the microstrip patch antenna, and the first feed being approximately 180 degrees out of phase with the second feed; and
a matching circuit coupling the first and second feeds with an integrated circuit, the matching circuit including a transmission line coupling the first feed with the second feed and creating a virtual short between the feeds. - View Dependent Claims (9, 10, 11)
-
-
12. A radio frequency identification transponder comprising:
-
a first patch antenna and a second patch antenna;
an integrated circuit having a first pair of terminals and a second pair of terminals; and
a first matching circuit for coupling the first patch antenna to the first pair of terminals, wherein the first matching circuit resonates at a first frequency; and
a second matching circuit for coupling the second patch antenna to the second pair of terminals, wherein the second matching circuit resonates at a second frequency. - View Dependent Claims (13, 14, 15)
-
-
16. In a radio frequency identification transponder for physical association with an object and for storing and communicating data regarding the object, the improvement comprising:
-
a first patch antenna and a second patch antenna;
an integrated circuit having a first pair of terminals and a second pair of terminals;
a first matching circuit for coupling the first patch antenna to the first pair of terminals, wherein the first matching circuit resonates at a first frequency; and
a second matching circuit for coupling the second patch antenna to the second pair of terminals, wherein the second matching circuit resonates at a second frequency. - View Dependent Claims (17, 18, 19)
-
-
20. A radio frequency identification transponder comprising:
-
a microstrip patch antenna providing electromagnetic coupling for far-field operation;
an integrated circuit; and
a matching circuit coupling the microstrip patch antenna with the integrated circuit includes a circuit loop that is sufficiently large to provide inductive coupling for near-field operation.
-
-
21. In a radio frequency identification transponder for physical association with an object for storing data regarding the object, the radio frequency identification transponder having a microstrip patch antenna, an integrated circuit, and a matching circuit coupling the microstrip patch antenna with the integrated circuit, the improvement comprising:
the matching circuit including a circuit loop which also functions as a near-field antenna.
-
22. A radio frequency identification transponder comprising:
-
a first layer including a substrate and a ground plane;
a second layer including first and second microstrip patch antennas, with each patch antenna extending toward a different side of the second layer, an integrated circuit, and first and second matching circuits coupling the first and second microstrip patch antennas, respectively, to the integrated circuit. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30)
-
-
31. In a radio frequency identification transponder for physical association with an object and for storing and communicating data regarding the object, the radio frequency identification transponder having an integrated circuit, the improvement comprising:
-
a first layer including a substrate and a ground plane;
a second layer including first and second microstrip patch antennas, with each patch antenna extending toward a different side of the second layer, an integrated circuit, and first and second matching circuits coupling the first and second microstrip patch antennas, respectively, to the integrated circuit; and
a third layer including a superstrate for protecting the second layer from an adverse condition of an operating environment. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38)
-
-
39. A radio frequency identification transponder comprising:
-
a microstrip patch antenna having an annular shape with an inner edge and an outer edge;
an integrated circuit;
a first feed and a second feed, each feed being coupled with an edge of the microstrip patch antenna, and the first feed being approximately 180 degrees out of phase with the second feed; and
a matching circuit coupling the first and second feeds with an integrated circuit, the matching circuit including a transmission line coupling the first feed with the second feed and creating a virtual short between the feeds. - View Dependent Claims (40, 41, 42, 43)
-
-
44. In a radio frequency identification transponder for physical association with a cylindrical object having a stem and for storing and communicating data regarding the object, the radio frequency identification transponder having a microstrip patch antenna and an integrated circuit, the improvement comprising:
-
the microstrip patch antenna having an annular shape with an inner edge and an outer edge;
a first feed and a second feed, each feed being coupled with an edge of the microstrip patch antenna, and the first feed being approximately 180 degrees out of phase with the second feed; and
a matching circuit coupling the first and second feeds with the integrated circuit, the matching circuit including a transmission line coupling the first feed with the second feed and creating a virtual short between the feeds, wherein the matching circuit is coupled with the inner edge of the microstrip patch antenna. - View Dependent Claims (45, 46, 47)
-
-
48. In a radio frequency identification transponder for physical association with a cylindrical object having a stem and for storing and communicating data regarding the object, the radio frequency identification transponder having a microstrip patch antenna and an integrated circuit, the improvement comprising:
-
the microstrip patch antenna having an annular shape with an inner edge and an outer edge;
a first feed and a second feed, each feed being coupled with an edge of the microstrip patch antenna, and the first feed being approximately 180 degrees out of phase with the second feed; and
a matching circuit coupling the first and second feeds with the integrated circuit, the matching circuit including a transmission line coupling the first feed with the second feed and creating a virtual short between the feeds, wherein the matching circuit is coupled with the outer edge of the microstrip patch antenna. - View Dependent Claims (49, 50, 51)
-
Specification