# US 5,352,990 A · Power matching network comprising an intermediate transmission line between a transistor amplifier output end and at least one open-end line

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- Number: US 5,352,990 A
- Document ID: US5352990A
- Status: Granted
- Kind: A
- Application number: 08/178,877
- Filed: 1994-01-06
- Granted: 1994-10-04
- Earliest claimed: 1993-01-07
- Assignees: NEC Corporation
- Inventors: Norio Goto
- Web page: https://patentgrep.com/patent/US5352990A

## CPC

- H03F 3/60: Amplifiers in which coupling networks have distributed constants, e.g. with waveguide resonators (H03F3/54 takes precedence)
- H03F 1/56: Modifications of input or output impedances, not otherwise provided for
- H03F 3/2176: {Class E amplifiers}
- H03F: AMPLIFIERS

## Abstract

In a power matching network which is used between a load and a transistor amplifier producing at its output end an amplified signal comprising a fundamental frequency signal and odd and even harmonic signals and comprises a matching circuit between the load and a line end, an open-end transmission line is connected to the output end and has a predetermined length shorter than a quarter wavelength of the fundamental frequency signal. An intermediate transmission line is connected between the output and the line ends and has a length of a quarter wavelength less the predetermined length. At least one open-end transmission line is connected to the line end and has a length of a quarter wavelength of the odd harmonic signal which is preferably composed of (2n+1)-th harmonic signals, where n represents integers starting at 1 and ending at a predetermined integer of at least 2. More preferably, the line end is connected to an additional transmission line which is either a 1/8 wavelength of the fundamental frequency signal long and has an end shorted for high frequency signals or is a 1/16 wavelength of the fundamental frequency signal long.

## Claims

### Claim 1

A power matching network for a transistor amplifier producing at its output end an amplified signal comprising a fundamental frequency signal and odd and even harmonic signals, said power matching network comprising:
an open-end transmission line connected to said output end and having a length of a 1/8 wavelength of said fundamental frequency signal;
an intermediate transmission line connected to said output end and having a line end and a length of said 1/8 wavelength;
at least one open-end transmission line connected to said line end and having a quarter wavelength of said odd harmonic signal; and
a matching circuit connected to said line end for said fundamental frequency signal.

### Claim 2 (depends on 1)

A power matching network as claimed in claim 1, further comprising an additional transmission line connected to said output end and having a length of a quarter wavelength of said fundamental frequency signal and an end shorted for high frequency signals.

### Claim 3 (depends on 1)

A power matching network as claimed in claim 1, further comprising an additional transmission line connected to said line end and having a length of said 1/8 wavelength and an end shorted for high frequency signals.

### Claim 4 (depends on 1)

A power matching network as claimed in claim 1, further comprising an open-end transmission line connected to said line end and a length of a 1/16 wavelength of said fundamental frequency signal.

### Claim 5 (depends on 1)

A power matching network as claimed in claim 1, wherein said at least one open-end transmission line consists of a plurality of open-end transmission lines having lengths of quarter wavelengths of (2n+1)-th harmonic signals, where n represents integers starting at 1 and ending at a predetermined integer which is equal at least to 2.

### Claim 6 (depends on 6)

A power matching network for a transistor amplifier producing at its output end an amplified signal comprising a fundamental frequency signal and odd and even harmonic signals, said power matching network comprising:
an open-end transmission line connected to said output end and having a predetermined length which is shorter than a quarter wavelength of said fundamental frequency signal and is not equal to a 1/8 wavelength of said fundamental frequency signal;
an intermediate transmission line connected to said output end and having a line end and a length which is equal to said quarter wavelength less said predetermined length;
at least one open-end transmission line connected to said line end and having a length of a quarter wavelength of said odd harmonic signal; and (claim 6 continued)
a matching circuit connected to said line end for said fundamental frequency signal.

### Claim 7 (depends on 6)

A power matching network as claimed in claim 6, wherein said at least one open-end transmission line consists of a plurality of open-end transmission lines having lengths of quarter wavelengths of (2n+1)-th harmonic signals, where n represents integer starting at 1 and ending at a predetermined integer which is equal at least to 2.

### Claim 8 (depends on 7)

A power matching network as claimed in claim 7, further comprising an additional transmission line connected to said output end and having a length of a quarter wavelength of said fundamental frequency signal and an end shorted for higher frequency signals.

### Claim 9 (depends on 7)

A power matching network as claimed in claim 7, further comprising an additional transmission line connected to said line end and having a length of a 1/8 wavelength of said fundamental frequency signal and an end shorted for high frequency signals.

### Claim 10 (depends on 7)

A power matching network as claimed in claim 7, further comprising an open-end transmission line connected to said line end and having a length of a 1/16 wavelength of said fundamental frequency signal.