Claims
- 1. A balancing/unbalancing (balun) structure for operating at frequency f1 and rejecting a frequency f2 comprising:
a printed circuit board (PCB); a balun on the PCB comprising:
first and second input ports for coupling to a differential signal, a third port connected to ground through a resistance, a fourth port for coupling to a single-ended signal corresponding to the differential signal, and a plurality of traces on the PCB connecting the first and second input ports, the third port and a tap point to the fourth port; a first λ2/4 element connected to the fourth port; a second λ2/4 element connected to the tap point; and a third λ2/4 element connecting the tap point to the fourth port.
- 2. The balun structure of claim 1, wherein the first and second input ports and the fourth port are on opposite sides of the balun structure.
- 3. The balun structure of claim 1, wherein the first and second input ports and the fourth port are on the same side of the balun structure.
- 4. The balun structure of claim 1, wherein the balun is a 180° hybrid.
- 5. The balun structure of claim 1, wherein a transmission distance from the first input port to the tap point is λ1/4.
- 6. The balun structure of claim 1, wherein the first λ2/4 element is oriented in a direction generally corresponding to a direction from the first and second input ports to the fourth port.
- 7. The balun structure of claim 1, wherein the third λ2/4 element is oriented in a direction generally perpendicular to a direction from the first and second input ports to the fourth port.
- 8. The balun structure of claim 1, wherein the second λ2/4 element is wrapped around the balun.
- 9. The balun structure of claim 1, wherein distance between adjacent traces is approximately twice PCB thickness.
- 10. The balun structure of claim 1, wherein the PCB includes two substrate layers, two tracing layers and a ground layer, and
wherein the plurality of traces that comprise the balun and the λ2/4 elements are formed on the two tracing layers and are folded over each other.
- 11. An f1 balun with an integrated f2 rejection filter comprising:
a printed circuit board (PCB); a plurality of transmission lines on the PCB forming the balun and connecting a first and second input ports, an isolation port and an output port, wherein the f2 rejection filter is wrapped around the plurality of transmission lines.
- 12. The f1 balun of claim 11, wherein the first and second input ports and the fourth port are on opposite sides of the balun.
- 13. The f1 balun of claim 11, wherein the first and second input ports and the fourth port are on the same side of the balun.
- 14. The f1 balun of claim 11, wherein the balun is a 180° hybrid.
- 15. The f1 balun of claim 11, wherein a transmission distance from a first input port of the two ports to a tap point is λ1/4.
- 16. The f1 balun of claim 11, wherein the f2 rejection filter includes a first folded element that is oriented in a direction generally corresponding to a direction from the first and second input ports to the fourth port.
- 17. The f1 balun of claim 16, wherein the f2 rejection filter includes a second folded element that is oriented in a direction generally perpendicular to a direction from the first and second input ports to the fourth port.
- 18. The f1 balun of claim 11, wherein distance between adjacent transmission lines is approximately twice PCB thickness.
- 19. The f1 balun of claim 11, wherein the plurality of transmission lines includes a plurality of folded λ1/4 elements.
- 20. The f1 balun of claim 11, wherein the at least one transmission line element includes a first folded element having a transmission length of λ2/4 and connected to the fourth port.
- 21. The f1 balun of claim 20, further including a second folded element having a transmission length of λ2/4 and connected to the tap point.
- 22. The f1 balun of claim 21, wherein the second folded element is wrapped around the plurality of transmission lines.
- 23. A balancing/unbalancing (balun) structure for operating at frequency f1 and rejecting a frequency f2 comprising:
first and second input ports for coupling to a differential signal; a third port connected to ground through a resistance; a fourth port for coupling to a single-ended signal corresponding to the differential signal; a plurality of traces on a PCB forming the balun structure and connecting the first and second input ports, the third port and a tap point to the fourth port; a first λ2/4 element connected to the fourth port; and a second λ2/4 element connecting the tap point to the fourth port, wherein the first and second λ2/4 elements are generally positioned around the balun structure.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is claims priority to U.S. patent application Ser. No. 10/232,620, filed on Sep. 3, 2002, entitled COMPACT BALUN FOR 802.11a APPLICATIONS, and to U.S. patent application Ser. No. 10/232,617, filed on Sep. 3, 2002, entitled COMPACT BALUN WITH REJECTION FILTER FOR 802.11a AND 802.11b SIMULTANEOUS OPERATION, which are incorporated by reference herein.
Continuations (2)
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Number |
Date |
Country |
Parent |
10232620 |
Sep 2002 |
US |
Child |
10704915 |
Nov 2003 |
US |
Parent |
10232617 |
Sep 2002 |
US |
Child |
10232620 |
Sep 2002 |
US |