Laminated balun transformer

• US 6,285,273 B1
• Filed: 03/12/1997
• Issued: 09/04/2001
• Est. Priority Date: 03/22/1996
• Status: Expired due to Term

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Morikawa, Takehiko
• Primary Examiner(s): MAI, ANH T
• Application Number:
  US08/815,708
• Time in Patent Office: 1,637 Days
• Field of Search: 333/116, 333/26, 336/200, 336/232, 336/223
• US Class Current: 336/200
• CPC Class Codes: H01F 17/0013 with stacked layers
• CPC Class Codes: H01F 19/04 Transformers or mutual inductances suitable for handling frequencies considerably beyond the audio range resonant circuits H03H
• CPC Class Codes: H01F 41/043 by thick film techniques
• CPC Class Codes: H01P 5/10 for coupling balanced lines or devices with unbalanced lines or devices
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor

Abstract

A laminated balun transformer includes a dielectric sheet for which a lead electrode is provided at its surface, dielectric sheets for which λ/4 striplines are provided at their surfaces respectively, and dielectric sheets for which ground electrodes are provided at their surfaces respectively. One pair of opposing striplines is provided with a dielectric sheet disposed therebetween so as to be electromagnetically coupled. The other pair of opposing striplines is provided with a dielectric sheet disposed therebetween so as to be electromagnetically coupled. An end of a stripline of one pair of striplines is electrically connected to an end of a stripline of the other pair of striplines through an external electrode.

Claims

1. A laminated balun transformer comprising at least two pairs of striplines, the striplines of each pair being exclusively electromagnetically coupled to one another through a respective dielectric layer, the two pairs of striplines being in parallel planes with respect to one another, and with another dielectric layer having a grounded electrode thereon interposed between said pairs of striplines.

2. A laminated balun transformer according to claim 1, further comprising an external grounded electrode connected to said grounded electrode interposed between said pairs of striplines, wherein said external grounded electrode is disposed on a surface of laminated balun transformer, and wherein one stripline from each of said two pairs of striplines is connected to said external grounded electrode via the grounded electrode.

3. A laminated balun transformer comprising:

a first dielectric sheet with a first stripline located at one surface thereof;

a second dielectric sheet with a second stripline exclusively electromagnetically coupled with said first stripline located at one surface thereof;

a third dielectric sheet with a first grounded electrode located at one surface thereof;

a fourth dielectric sheet with a third stripline located at one surface thereof;

a fifth dielectric sheet with a fourth stripline exclusively electromagnetically coupled with said third stripline located at one surface thereof; and

electrically connecting means for electrically connecting said first stripline and said fourth stripline, wherein said first, said second, said third, said fourth, and fifth dielectric sheets are in a stacked relationship one above another in a laminated structure.

4. A laminated balun transformer according to claim 3, further comprising:

a sixth dielectric sheet with a second ground electrode located at one surface thereof;

and

a seventh dielectric sheet with a third ground electrode located at one surface thereof,

wherein said sixth, said first, said second, said third, said fourth, said fifth, and said seventh dielectric sheets are in a stacked relationship one above another in a laminated structure.

5. A laminated balun transformer according to claim 4, further comprising an eighth dielectric sheet with a lead electrode located at one surface thereof, wherein said eighth, said sixth, said first, said second, said sixth, said third, said fourth, said fifth, and said seventh dielectric sheets are in a stacked relationship one above another in a laminated structure.

6. A laminated transformer in accordance with claim 3, wherein said electrical connecting means includes via holes provided inside the laminated structure.

7. A laminated transformer in accordance with claim 3, wherein said striplines are spiral shaped.

8. A laminated transformer in accordance with claim 3, wherein said electrical connecting means includes external electrodes provided on side faces of the laminated structure.

9. A laminated balun transformer according to claim 3, further comprising an external grounded electrode connected to said grounded electrode interposed between said second and third striplines, wherein said external grounded electrode is disposed on a surface of laminated balun transformer, and wherein said second and third striplines are connected to said external grounded electrode via the grounded electrode.

10. A laminated balun transformer used for a balanced-unbalanced circuit for taking out balanced signals from unbalanced signals or unbalanced signals from balanced signals, comprising at least two pairs of striplines, the striplines of each pair being exclusively electromagnetically coupled to one another through a respective dielectric layer, the two pairs of striplines being in parallel planes with respect to one another, and with another dielectric layer having a grounded electrode thereon interposed between said pairs of striplines.

11. A laminated balun transformer according to claim 10, wherein said grounded electrode includes a first, second and third grounded electrode, one pair of striplines is disposed between said first grounded electrode and said second ground electrode and the other pair of striplines is disposed between said first grounded electrode and the third electrode.

12. A laminated balun transformer according to claim 10, further comprising an external grounded electrode connected to said grounded electrode interposed between said pairs of striplines, wherein said external grounded electrode is disposed on a surface of laminated balun transformer, and wherein one stripline from each of said at least two pairs of striplines is connected to said external grounded electrode via the ground electrode.