Magnetically coupling near-field RFID antenna
View Patent ↗An improved magnetically coupling near-field RFID antenna is embodied as a magnetic H-field coupler, and the near-field RFID antenna is embodied as a looped and/or frame-shaped antenna. The looped and/or frame-shaped antenna comprises a looped or frame-shaped strip conductor. The strip conductor is arranged set apart from a ground surface parallel thereto. A dielectric is interposed. The start and the end of the strip conductor end close to each other forms a gap or spacing. The start of the strip conductor is fed to ground. The end of the strip conductor is terminated by a terminating resistor. The terminating resistor is connected between the end of the strip conductor and a ground surface.
1. A magnetically coupling near-field RFID antenna comprising:
a magnetic H-field coupler,
a looped and/or frame-shaped antenna comprising a looped or frame-shaped strip conductor,
the strip conductor arranged set apart from a ground surface parallel thereto, a dielectric being interposed,
the start and the end of the strip conductor end close to each other forming a gap or spacing,
the start of the strip conductors being fed to said ground surface,
the end of the strip conductors being terminated by a terminating resistor,
the terminating resistor being connected between the end of the strip conductor and said ground surface.
2. The near-field RFID antenna as claimed in claim 1 , wherein the dielectric is formed from a substrate.
3. The near-field RFID antenna as claimed in claim 2 , wherein the dielectric has an ∈ r which is greater than or equal to 1 and less than 10.
4. The near-field RFID antenna as claimed in claim 2 , wherein the substrate comprises FR4 and/or wherein the substrate comprises a dielectric having a dielectric constant ∈ r lying between 4.0 and 4.7.
5. The near-field RFID antenna as claimed in claim 1 , wherein the radius of the looped and/or frame-shaped antenna is less than 2.7 cm.
6. The near-field RFID antenna as claimed in claim 5 , wherein the radius of the looped and/or frame-shaped antenna is less than or equal to 1.9 cm.
7. The near-field RFID antenna as claimed in claim 1 , wherein the looped and/or frame-shaped antenna is formed so as to be circular, oval, square, rectangular or n-polygonal with portions assembled in a straight or curved manner.
8. The near-field RFID antenna as claimed in claim 1 , wherein the terminating resistor corresponds to the line impedance.
9. The near-field RFID antenna as claimed in claim 1 , wherein the wave resistance of the strip conductor is approximately 50 ohms, in a substrate consisting of or using FR4 and/or using a substrate having a dielectric constant ∈ r of between 4.0 and 4.7.
10. The near-field RFID antenna as claimed in claim 1 , wherein the terminating resistor is provided on the upper side of the dielectric and is connected to the ground surface, which is provided on the underside of the dielectric, via one or more through-contacts or connecting lines.
11. The near-field RFID antenna as claimed in claim 1 , wherein the terminating resistor is separated in a recessed region from the ground surface and is connected to the ground surface via one or more lines and wherein the opposite connection side of the terminating resistor is connected to one end of the strip conductor, which is located on the upper side on the dielectric, via at least one line or via a through-contact.
12. The near-field RFID antenna as claimed in claim 1 , wherein the spacing between the start and the end of the strip conductor is less than 10%, in particular less than 8%, 7%, 6%, 5%, 4%, 3%, 2% or less than 1% of the total length of the strip conductor.