# US 7,613,434 B2 · Multiplexer and wireless receiver

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- Number: US 7,613,434 B2
- Document ID: US7613434B2
- Status: Granted
- Kind: B2
- Application number: 11/686,048
- Filed: 2007-03-14
- Published: 2008-02-14
- Granted: 2009-11-03
- Earliest claimed: 2006-08-08
- Assignees: Kabushiki Kaisha Toshiba
- Inventors: Fumihiko Aiga; Hiroyuki Kayano; Tatsunori Hashimoto; Noritsugu Shiokawa
- Web page: https://patentgrep.com/patent/US7613434B2

## CPC

- H01P 1/2135: {using strip line filters (H01P1/2131 takes precedence)}
- H04B 1/0057: {using diplexing or multiplexing filters for selecting the desired band}
- H01P: WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE (operating at optical frequencies G02B)
- H04B: TRANSMISSION

## Abstract

A multiplexer includes: a first band-pass filter for a first channel, which is formed in a microstrip line on a dielectric substrate and has a first branching characteristic having a center frequency of f1 and an attenuation pole at a frequency of fa1; and a second band-pass filter for a second channel, which is formed in a microstrip line on a dielectric substrate and has a second branching characteristic having a center frequency of f2 and an attenuation pole at a frequency of fa2. The following relationships (1) to (5) are satisfied: (1) f1<f2; (2) f1<fa1; (3) fa2<f2; (4) f2−fa1<(f2−f1)/2; and (5) fa2−f1<(f2−f1)/2. The second branching characteristic exhibits −20 dB or less at the frequency of fa1 and the first branching characteristic exhibits −20 dB or less at the frequency of fa2.

## Claims

### Claim 1

A multiplexer comprising:
a first band-pass filter for a first channel, which is formed in a microstrip line on a dielectric substrate and has a first branching characteristic having a center frequency of f1 and an attenuation pole at a frequency of fa1; and
a second band-pass filter for a second channel, which is formed in a microstrip line on a dielectric substrate and has a second branching characteristic having a center frequency of f2 and an attenuation pole at a frequency of fa2,
wherein the following relationships (1) to (5) are satisfied:
f1<f2 (1);
f1<fa1 (2);
fa2<f2 (3);
f2−fa1<(f2−f1)/2 (4); and
fa2−f1<(f2−f1)/2 (5), and
wherein the second branching characteristic exhibits −20 dB or less at the frequency of fa1 and the first branching characteristic exhibits −20 dB or less at the frequency of fa2.

### Claim 2 (depends on 1)

The multiplexer according to claim 1,
wherein at least a part of the first and second band-pass filter has a superconductive characteristic.

### Claim 3 (depends on 1)

The multiplexer according to claim 1,
wherein the first and second band-pass filters are formed on the same dielectric substrate.

### Claim 4 (depends on 1)

A wireless receiver comprising:
the multiplexer according to claim 1 that branches a received signal from an antenna, the multiplexer further comprising first and second channel output portions for the first and second channels, respectively;
first and second low noise amplifiers connected to the first and second channel output portions, respectively; and
first and second mixers, each including:
an input portion connected to the corresponding low noise amplifier; and
an output portion connected to a corresponding baseband processor.

### Claim 5 (depends on 1)

A wireless receiver comprising:
the multiplexer according to claim 1 that branches a received signal from an antenna, the multiplexer further comprising:
a third band-pass filter for a guard band between the first channel and the second channel; and
first to third output portions for the first to third band-pass filters, respectively;
first to third low noise amplifiers connected to the first to third output portions, respectively;
first and second mixers, each including:
an input portion configured to connect to the corresponding low noise amplifier; and
an output portion connected to a corresponding baseband processor;
a first switch that selects an output state of the third band-pass filter either an open state where an output of the third band-pass filter is opened or a close state where the output of the third band-pass filter is multiplexed with an output of the first band-pass filter; and
a second switch that selects an output state of the first filter either a close state where the output from the first band-pass filter is multiplexed with an output of the second filter or a pass state where the output from the first band-pass filter passes through to the first mixer without being multiplexed.

### Claim 6 (depends on 5)

The wireless receiver according to claim 5, further comprising first to third delay circuits provided at the subsequent stage of the first to third low noise amplifiers, respectively.

### Claim 7 (depends on 5)

The wireless receiver according to claim 5, further comprising a line connecting an input portion of the multiplexer and one of the first and second band-pass filters, the line having a variable electric length.

### Claim 8 (depends on 5)

The wireless receiver according to claim 5,
wherein a gain of each of the first to third low noise amplifiers is variable.

### Claim 9

A multiplexer comprising:
a first band-pass filter for a first channel, which is formed in a microstrip line on a dielectric substrate and has a first branching characteristic having a center frequency of f1 and an attenuation pole at a frequency of fa1;
a second band-pass filter for a second channel, which is formed in a microstrip line on a dielectric substrate and has a second branching characteristic having a center frequency of f2 and attenuation poles at frequencies of fa2 and fb2 higher than fa2,
a third band-pass filter for a third channel, which is formed in a microstrip line on a dielectric substrate and has a third branching characteristic having a center frequency of f3 and attenuation poles at frequencies of fa3 and fb3 higher than fa3; and
a fourth band-pass filter for a fourth channel, which is formed in a microstrip line on a dielectric substrate and has a fourth branching characteristic having a center frequency of f4 and an attenuation pole at a frequency of fa4;
an input portion; and
a delay circuit directly connected to the input portion;
wherein the following relationships (1) to (15) are satisfied:
f1<f2 (1)
f1<fa1 (2);
fa2<f2 (3);
f2−fa1<(f2−f1)/2 (4);
fa2−f1<(f2−f1)/2 (5);
f2<f3 (6);
f2<fb2 (7);
fa3<f3 (8);
f3−fb2<(f3−f2)/2 (9);
fa3−f2<(f3−f2)/2 (10);
f3<f4 (11);
f3<fb3 (12);
fa4<f4 (13);
f4−fb3<(f4−f3)/2 (14); and
fa4−f3<(f4−f3)/2 (15),
wherein the second branching characteristic exhibits −20 dB or less at the frequency of fa1 and the first branching characteristic exhibits −20 dB or less at the frequency of fa2,
wherein the third branching characteristic exhibits −20 dB or less at the frequency of fb2 and the second branching characteristic exhibits −20 dB or less at the frequency of fa3,
wherein the fourth branching characteristic exhibits −20 dB or less at the frequency of fb3 and the third branching characteristic exhibits −20 dB or less at the frequency of fa4, and
wherein one of the first to fourth band-pass filters is directly connected to the delay circuit.

### Claim 10 (depends on 9)

A wireless receiver comprising:
the multiplexer according to claim 9 that branches a received signal from an antenna, the multiplexer further comprising first to fourth channel output portions for the first to fourth channels, respectively;
first to fourth low noise amplifiers connected to the first to fourth channel output portions, respectively; and
first to fourth mixers, each including:
an input portion connected to the corresponding low noise amplifier; and
an output portion connected to a corresponding baseband processor.

### Claim 11

A multiplexer comprising:
a first band-pass filter for a first channel, which is formed in a microstrip line on a dielectric substrate and has a first branching characteristic having a center frequency of f1 and an attenuation pole at a frequency of fa1;
a second band-pass filter for a second channel, which is formed in a microstrip line on a dielectric substrate and has a second branching characteristic having a center frequency of f2 and attenuation poles at frequencies of fa2 and fb2 higher than fa2,
a third band-pass filter for a third channel, which is formed in a microstrip line on a dielectric substrate and has a third branching characteristic having a center frequency of f3 and attenuation poles at frequencies of fa3 and fb3 higher than fa3; and
a fourth band-pass filter for a fourth channel, which is formed in a microstrip line on a dielectric substrate and has a fourth branching characteristic having a center frequency of f4 and an attenuation pole at a frequency of fa4;
an input portion; and
a fifth and sixth delay circuit, each directly connected to the input portion; and
a first to fourth delay circuit, each directly connected to the first to fourth band-pass filters,
wherein the following relationships (1) to (15) are satisfied:
f1<f2 (1);
f1<fa1 (2);
fa2<f2 (3);
f2−fa1<(f2−f1)/2 (4);
fa2−f1<(f2−f1)/2 (5);
f2<f3 (6);
f2<fb2 (7);
fa3<f3 (8);
f3−fb2<(f3−f2)/2 (9);
fa3−f2<(f3−f2)/2 (10);
f3<f4 (11);
f3<fb3 (12);
fa4<f4 (13);
f4−fb3<(f4−f3)/2 (14); and
fa4−f3<(f4−f3)/2 (15),
wherein the second branching characteristic exhibits −20 dB or less at the frequency of fa1 and the first branching characteristic exhibits −20 dB or less at the frequency of fa2,
wherein the third branching characteristic exhibits −20 dB or less at the frequency of fb2 and the second branching characteristic exhibits −20 dB or less at the frequency of fa3,
wherein the fourth branching characteristic exhibits −20 dB or less at the frequency of fb3 and the third branching characteristic exhibits −20 dB or less at the frequency of fa4, and
wherein each of the first to fourth delay circuits is connected to the input portion through either the fifth or sixth delay circuit.

### Claim 12 (depends on 11)

A wireless receiver comprising:
the multiplexer according to claim 11 that branches a received signal from an antenna, the multiplexer further comprising first to fourth channel output portions for the first to fourth channels, respectively;
first to fourth low noise amplifiers connected to the first to fourth channel output portions, respectively; and
first to fourth mixers, each including:
an input portion connected to the corresponding low noise amplifier; and
an output portion connected to a corresponding baseband processor.