Unbalanced-to-balanced converter

• US 6,040,745 A
• Filed: 11/25/1997
• Issued: 03/21/2000
• Est. Priority Date: 11/26/1996
• Status: Expired due to Term

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Hashimoto, Takuya, Tanaka, Hiroaki, Sasaki, Yutaka
• Primary Examiner(s): Pascal, Robert
• Assistant Examiner(s): Bettendorf, Justin P.
• Application Number:
  US08/978,402
• Time in Patent Office: 847 Days
• Field of Search: 333/25, 333/26
• US Class Current: 333/26
• CPC Class Codes: H01P 5/10 for coupling balanced lines or devices with unbalanced lines or devices

Abstract

An unbalanced-to-balanced converter (balun) comprising three distributed-constant lines. In one distributed-constant line, a standing wave is generated. Disposed adjacent thereto is another distributed-constant line to which the power of the standing wave is transferred. A signal input to the unbalanced-to-balanced converter is divided into two signals having phases 180 degrees apart and the same level.

Claims

1. An unbalanced-to-balanced converter for use at a given wavelength, comprising:

first, second, and third distributed-constant lines disposed in this order and arranged for being electromagnetically coupled with each other;

said first, second, and third distributed-constant lines having coupling sections whose length is substantially one fourth of said given wavelength; and

a first end of said first distributed-constant line is an input terminal, said first end of said first distributed-constant line is connected to a first end of said second distributed-constant line, a second end of said second distributed-constant line and a first end of said third distributed-constant line are grounded, a second end of said first distributed-constant line is a first output terminal, and a second end of said third distributed-constant line is a second output terminal,

wherein said first, second and third distributed-constant lines are disposed so that in response to an input signal received at said input terminal, a pair of output signals appear at said first and second output terminals having phases substantially 180°

apart and having substantially the same level, and

wherein said first, second and third distributed-constant lines are at least 10 μ

m apart.

2. A converter as in claim 1, wherein each of said output signals has substantially half the power of said input signal.

3. An unbalanced-to-balanced converter for use at a given wavelength, comprising:

first, second, and third distributed-constant lines disposed in this order and arranged for being electromagnetically coupled with each other;

said first, second, and third distributed-constant lines having coupling sections whose length is substantially one fourth of said given wavelength; and

a first end of said first distributed-constant line is an input terminal, said first end of said first distributed-constant line is connected to a first end of said second distributed-constant line, a second end of said second distributed-constant line and a first end of said third distributed-constant line are grounded, a second end of said first distributed-constant line is a first output terminal, and a second end of said third distributed-constant line is a second output terminal,

wherein said first, second and third distributed-constant lines are disposed substantially parallel with each other on a dielectric substrate, and

wherein said first, second and third distributed-constant lines are at least 10 μ

m apart.

4. A converter as in claim 3, wherein said first, second and third distributed-constant lines are constituted by respective microstriplines.

5. A converter as in claim 3, wherein said first, second and third distributed-constant lines are constituted by respective striplines.

6. An unbalanced-to-balanced converter for use at a given wavelength, comprising:

first, second, and third distributed-constant lines disposed in this order and arranged for being electromagnetically coupled with each other;

said first, second, and third distributed-constant lines having coupling sections whose length is substantially one fourth of said given wavelength; and

a first end of said first distributed-constant line is an input terminal, said first end of said first distributed-constant line is connected to a first end of said second distributed-constant line, a second end of said second distributed-constant line and a first end of said third distributed-constant line are grounded, a second end of said first distributed-constant line is a first output terminal, and a second end of said third distributed-constant line is a second output terminal,

wherein said first, second and third distributed constant lines are at least 10 μ

m apart.