Variable impedance matching circuit

• US 20040104785A1
• Filed: 09/29/2003
• Published: 06/03/2004
• Est. Priority Date: 12/02/2002
• Status: Abandoned Application

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Kim, Cheon Soo, Park, Mun Yang, Park, Pil Jae
• Application Number:
  US10/671,524
• Publication Number:
  US 20040104785A1
• Time in Patent Office: Days
• US Class Current: 333/33
• CPC Class Codes: H01P 1/185 using a diode or a gas filled discharge tube
• CPC Class Codes: H01P 5/028 between strip lines

Abstract

The present invention is directed to a circuit capable of matching variable impedances, and implements the variable impedance matching circuit by varying an electrical length of a transmission line by means of external control signals. In the L or π type matching circuit using inductance and capacitance as lumped elements, the variable impedance matching circuit is implemented by changing impedance values of the variable inductance and variable capacitance as lumped elements which have been made to be controlled, or by changing a topology of a circuit network by external control signals. Therefore, the variable impedance matching circuit according to the present invention enables it possible to electrically control an impedance of interest from arbitrary impedances, thereby a radio frequency circuit to which the variable impedance matching circuit belongs can be controlled, and the matching circuit can be implemented with arbitrary complex loads from any RF signal sources.

Claims

1. A variable impedance matching circuit having at least one stub lines connected in parallel or serial to a transmission line, characterized in that,

said at least one stub lines and said transmission line comprises at least one variable transmission line block changing an electrical length of the transmission line using at least one of switches operated by external control signal(s).

2. The variable impedance matching circuit as claimed in claim 1, wherein said at least one of switches are a MOSFET or a Pin diode.

3. A π

type variable impedance matching circuit comprising;

a first, a second, and a third lumped element connected with a shape of π

type;

at least one of switches which are capable of being operated by external control signals, connected to connection point(s) of said lumped elements,

wherein a topology is changed by selecting input/output ports or grounds using said at least one of switches.

4. A π

type variable impedance matching circuit as claimed in claim 3,

wherein said first, second, and third lumped elements are variable inductances or variable capacitances.

5. A L type variable impedance matching circuit using lumped elements, characterized in that

a first and second lumped elements connected with a shape of L type;

and

at least one of switches which are capable of being operated by external control signals, connected to connection point(s) of said lumped elements,

wherein a topology is changed by selecting input/output ports or grounds using said at least one of switches.

6. A L type variable impedance matching circuit as claimed in claim 5,

wherein said first, and second lumped elements are variable inductances or variable capacitances.