COMPOSITE RIGHT/LEFT HANDED (CRLH) HYBRID-RING COUPLERS

• US 20090002093A1
• Filed: 05/16/2008
• Published: 01/01/2009
• Est. Priority Date: 03/26/2004
• Status: Active Grant

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Itoh, Tatsuo, Okabe, Hiroshi, Lin, I-Hsiang, Caloz, Christophe
• Granted Patent: US 7,675,384 B2
• Time in Patent Office: Days
• US Class Current: 333/120
• CPC Class Codes: H01P 5/227 90° branch line couplers

Abstract

High-frequency couplers and coupling techniques are described utilizing artificial composite right/left-handed transmission line (CRLH-TL). Three specific forms of couplers are described; (1) a coupled-line backward coupler is described with arbitrary tight/loose coupling and broad bandwidth; (2) a compact enhanced-bandwidth hybrid ring coupler is described with increased bandwidth and decreased size; and (3) a dual-band branch-line coupler that is not limited to a harmonic relation between the bands. These variations are preferably implemented in a microstrip fabrication process and may use lumped-element components. The couplers and coupling techniques are directed at increasing the utility while decreasing the size of high-frequency couplers, and are suitable for use with separate coupler or couplers integrated within integrated devices.

Claims

1. A hybrid-ring coupler apparatus for generating separate signal channels from a radio-frequency input, comprising:

a plurality of input lines configured for receiving an input signal;

a plurality of output lines interposed with said input lines; and

a plurality of transmission lines, each transmission line (TL) connecting between neighboring said input line and said output line to form a ring;

wherein at least a portion of said TLs incorporates a composite right/left handed (CRLH) TL; and

wherein capacitance and inductance contributions of a left-handed (LH) section and a right-handed (RH) section of said CRLH-TL are chosen so that a phase response of said CRLH-TL is dominated by an LH contribution at below a center frequency, while the phase response is dominated by an RH contribution at above the center frequency.

2. An apparatus as recited in claim 1, further comprising a 90°

or 180°

, isolated, output or combination along said TLs.

3. An apparatus as recited in claim 1, wherein said LH-TL section comprises a unit sell comprising a series capacitor with a shunt inductor.

4. An apparatus as recited in claim 3, wherein said LH-TL section comprises a lumped element capacitor in series with a lumped element shunt-inductor.

5. An apparatus as recited in claim 3, wherein said LH-TL section generates a −

90°

phase rotation which replaces a +270°

phase rotation of a conventional RH-TL.

6. An apparatus as recited in claim 1, wherein said CRLH TL comprises RH-TL and LH-TL sections providing a total phase rotation of −

90°

.

7. An apparatus as recited in claim 6:

wherein said RH-TL and LH-TL sections comprise three LH-TL sections and three RH-TL sections; and

wherein said three LH-TL sections each generate a −

35°

rotation and said three RH-TL sections each generate 5°

rotation to provide the total of −

90°

of phase rotation.

8. An apparatus as recited in claim 1, wherein said CRLH TL comprises a unit cell.

9. An apparatus as recited in claim 8:

wherein said unit cell comprises a series combination of a right-handed inductor and a left-handed capacitor; and

wherein said series combination of said right-handed inductor and said left-handed capacitor is coupled to a paralleled combination of a right-handed shunt capacitor and a left-handed shunt inductor.

10. An apparatus as recited in claim 1, wherein said CRLH-TL comprises alternating left-handed (LH) capacitors and right-handed (RH) TL sections coupled in series, and LH inductors shunting said RH-TL sections, respectively.

11. A hybrid-ring coupler apparatus for generating separate signal channels from a radio-frequency input, comprising:

a plurality of input lines configured for receiving an input signal;

a plurality of output lines interposed with said input lines; and

a plurality of transmission lines, each transmission line (TL) connecting between neighboring said input line and said output line to form a ring;

wherein at least a portion of said TLs incorporates a composite right/left handed (CRLH) TL.

12. An apparatus as recited in claim 11, wherein said CRLH TL comprises a unit cell.

13. An apparatus as recited in claim 11:

wherein said unit cell comprises a series combination of a right-handed inductor and a left-handed capacitor; and

wherein said series combination of said right-handed inductor and said left-handed capacitor is coupled to a paralleled combination of a right-handed shunt capacitor and a left-handed shunt inductor.

14. An apparatus as recited in claim 11, wherein said CRLH-TL comprises alternating left-handed (LH) capacitors and right-handed (RH) TL sections coupled in series, and LH inductors shunting said RH-TL sections, respectively.

15. A hybrid-ring coupler apparatus for generating separate signal channels from a radio-frequency input, comprising:

a plurality of input lines configured for receiving an input signal;

a plurality of output lines interposed with said input lines; and

a plurality of transmission lines, each transmission line (TL) connecting between neighboring said input line and said output line to form a ring;

wherein at least a portion of said TLs comprises a composite right/left-handed (CRLH) TL having RH-TL and LH-TL sections providing a total phase rotation of −

90°

.

16. An apparatus as recited in claim 15:

wherein said RH-TL and LH-TL sections comprise three LH-TL sections and three RH-TL sections; and

wherein said three LH-TL sections each generate a −

35°

rotation and said three RH-TL sections each generate 5°

rotation to provide the total of −

90°

of phase rotation.