Balun with series-connected balanced-signal lines

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Prior Publication Data

US 2009/0243750 Al

Oct. 1, 2009

Int. CI.

H03H 7/42 (2006.01)
H03H 7/38 (2006.01)

U.S. CI 333/26:333/33

Field of Classification Search 333/25,

333/26, 33, 238 See application file for complete search history.

References Cited

U.S. PATENT DOCUMENTS

3,103,638 A * 9/1963 Greuet 333/127

3,827,001 A * 7/1974 Laughlin 333/127

4,288,762 A * 9/1981 Laughlin 333/117

4,719,699 A * 1/1988 Dashetal 30/90.1

4,825,220 A 4/1989 Edward etal.

5,121,090 A * 6/1992 Garuts et al 333/124

5,977,842 A * 11/1999 Brown etal 333/26

5,982,252 A 11/1999 Werlau

6,130,588 A * 10/2000 Gallivan et al 333/25

6,285,273 Bl 9/2001 Morikawa

6,750,752 B2 6/2004 Werlau
7,190,240 B2 3/2007 Podell

OTHER PUBLICATIONS

The Southgate Amateur Radio Club web page "Techtips Coax Balun," http://www.southgatearc.org/techtips/coax_balun.htm, byline given as "G8MNY," downloaded Aug. 3, 2007. MicrowaveslOl .com Microwave Encyclopedia web page, "Baluns," http://www.microwavesl01.com/encyclopedia/baluns.cfm, updated Nov. 28, 2006 and downloaded Aug. 1, 2007. H.T. Kim et al, "Ultra-wideband uniplaner MMIC balun using field transformations," Electronics Letters vol. 2 No. 6, Mar. 16, 2006.

(Continued)

Primary Examiner—Dean O Takaoka

(74) Attorney, Agent, or Firm—Kolisch Hartwell,

PC

(57)

ABSTRACT

A balun may include series-coupled balanced-signal lines. In some examples, a balun may include a first transmission line having a first unbalanced signal port on which an unbalanced signal may exist relative to circuit ground; a second transmission line having a first balanced-signal port may be connected in series with a third transmission line having a second balanced-signal port. In some examples, a fourth transmission line may be coupled to the first transmission line and have a third balanced-signal port. A fifth transmission line may be connected in series with the fourth transmission line and have a fourth balanced-signal port. In some examples, the transmission lines may be coaxial. Balanced signals may exist between the first and second balanced-signal ports and between the third and fourth balanced-signal ports. Seriesconnected coaxial transmission lines may be formed of a single coaxial line with a gap in the outer conductor separating the two coaxial transmission lines.

17 Claims, 4 Drawing Sheets

OTHER PUBLICATIONS

Nai-Shuo Cheng et al, "A 120-W X-Band Spatially Combined Solid-
State Amplifier," IEEE Transactions on Microwave Theory and Tech-
niques vol. 47 No. 12 pp. 2557 through 2561, Dec. 1999.
Angelos Alexanian, doctoral dissertation, "Planar and Distributed
Spatial Power Combiners," University of California Santa Barbara,
Jun. 1997.

HongmingAn, et al, "A 50:1 Bandwidth Cost-Effective Coupler with
Sliced Coaxial Cable," IEEE MTT-S Digest, 1996.
Paul Horowitz et al., "Stubs, baluns, and transformers," The Art of
Electronics section 13.10, pp. 881 through 882, Second Edition
Copyright 1989 Cambridge University Press.

Valerie Illingworth, editor, definition of the word "balun," The Penguin Dictionary of Electronics p. 30, Second Edition Copyright 1988 Penguin Books.

Kenneth J. Russell, "Microwave Power Combining Techniques," IEEE Transactions on Microwave Theory and Techniques vol. MTT27 No. 5 pp. 472 through 478, May 1979.

C.W. Gerst, "Electrically Short 90° Couplers Utilizing Lumped Capacitors," Microwave Symposium Digest, G-MLL International vol. 67, Issue 1, pp. 58 through 62, May 1967. G.D. Monteath, "CoupledLransmission Lines as Symmetrical Directional Couplers," Proc. IEE, Vol. 102, Part B, No. 3, pp. 383 through 392, May 1955.

* cited by examiner