DEMULTIPLEXING APPARATUS AND METHOD OF DESIGNING THE APPARATUS

• US 20180248569A1
• Filed: 04/27/2018
• Published: 08/30/2018
• Est. Priority Date: 11/04/2015
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: TAKENAKA, Isao
• Granted Patent: US 10,298,273 B2
• Time in Patent Office: Days
• CPC Class Codes: H03F 1/565 using inductive elements
• CPC Class Codes: H03F 2200/111 the amplifier being a dual or triple band amplifier, e.g. 900 and 1800 MHz, e.g. switched or not switched, simultaneously or not
• CPC Class Codes: H03F 2200/171 A filter circuit coupled to the output of an amplifier
• CPC Class Codes: H03F 2200/387 A circuit being added at the output of an amplifier to adapt the output impedance of the amplifier
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 2203/7209 the gated amplifier being switched from a first band to a second band
• CPC Class Codes: H03F 3/19 with semiconductor devices only
• CPC Class Codes: H03F 3/21 with semiconductor devices only H03F3/245 takes precedence
• CPC Class Codes: H03F 3/245 with semiconductor devices only
• CPC Class Codes: H03F 3/72 Gated amplifiers, i.e. amplifiers which are rendered operative or inoperative by means of a control signal
• CPC Class Codes: H03H 11/34 Networks for connecting several sources or loads working on different frequencies or frequency bands, to a common load or source for use in multiplex transmission systems H04J1/00
• CPC Class Codes: H03H 7/38 Impedance-matching networks
• CPC Class Codes: H04B 1/0057 using diplexing or multiplexing filters for selecting the desired band
• CPC Class Codes: H04B 1/006 using switches for selecting the desired band H04B1/0057 takes precedence
• CPC Class Codes: H04B 1/50 using different frequencies for the two directions of communication

Abstract

A demultiplexing apparatus according to the present disclosure includes an amplifier that amplifies transmission signals in three or more communication bands having different frequency bands; multiple signal paths which are commonly provided for an output terminal of the amplifier and on which the signals in the corresponding communication bands are propagated; and multiple transmission-reception filters which are provided on the multiple signal paths, and each of which isolates a transmission signal and a reception signal of the corresponding communication band from each other. The gains of the amplifier in the frequency bands of multiple reception signals are smaller than the gains of the amplifier in the frequency bands of multiple transmission signals.

Claims

1. A demultiplexing apparatus comprising:

an amplifier that amplifies transmission signals in three or more communication bands;

three or more signal paths provided from an output terminal of the amplifier, each of the signal paths configured to propagate transmission signals corresponding to a different one of the three or more communication bands; and

three or more transmission-reception filters, each of the transmission-reception filters provided in a different one of the signal paths and configured to isolate transmission signals and reception signals of a corresponding communication band,

wherein, for each communication band, a gain of the amplifier in a reception frequency band of the communication band is less than a gain of the amplifier in a transmission frequency band of the communication band.

5. The demultiplexing apparatus according to claim 1, further comprising:

a common matching circuit provided between the output terminal and a common node of the signal paths; and

an individual matching circuit provided in each of the signal paths between the common node and the corresponding transmission-reception filter.

7. The demultiplexing apparatus according to claim 5,

wherein phases of a second load impedance in the reception frequency band of each of the communication bands, when viewing the transmission-reception filters from the common node and when plotted in a second Smith chart normalized with respect to impedance of the signal paths, substantially coincide with each other.

9. The demultiplexing apparatus according to claim 7,

wherein each of the individual matching circuits is configured so that an amount of phase rotation of the second load impedance due to the provision of the individual matching circuit is minimized in the second Smith chart.

11. The demultiplexing apparatus according to claim 9,

wherein each individual matching circuit is a high pass filter type matching circuit or a low pass filter type matching circuit.

13. The demultiplexing apparatus according to claim 5,

wherein the common matching circuit and each of the individual matching circuits includes an LC filter of one or more stages, and

wherein the LC filters of each individual matching circuit has more stages than the LC circuit of the common matching circuit.

15. The demultiplexing apparatus according to claim 5,

wherein each of the individual matching circuits is incorporated in the corresponding transmission-reception filter.

17. The demultiplexing apparatus according to claim 5, further comprising:

a switch that is provided between the common matching circuit and the individual matching circuits and that is configured to selectively connect/disconnect at least one of the signal paths, among all of the signal paths, to the common node.

19. The demultiplexing apparatus according to claim 17,

wherein the switch is configured to connect at least two of the signal paths, among all of the signal paths, to the common node.

2. A demultiplexing apparatus comprising:

an amplifier that amplifies transmission signals in three or more communication bands;

three or more signal paths provided from an output terminal of the amplifier, each of the signal paths configured to propagate transmission signals corresponding to a different one of the three or more communication bands; and

three or more transmission-reception filters, each of the transmission-reception filters provided in a different one of the signal paths and configured to isolate transmission signals and reception signals of a corresponding communication band,

wherein, for each communication band, a first load impedance in a reception frequency band of the communication band, when viewing the corresponding transmission-reception filter from the output terminal and when plotted on a Smith chart normalized with respect to output impedance of the amplifier, is positioned in an area where the phase is apart from a maximum point of a gain of the amplifier by 45 degrees or more.

3. The demultiplexing apparatus according to claim 2,

wherein the first load impedance is positioned in an area where the phase is apart from the maximum point by 90 degrees or more in the first Smith chart.

4. The demultiplexing apparatus according to claim 2,

wherein, for each communication band, a gain of the amplifier in the reception frequency band of the communication band is less than a gain of the amplifier in a transmission frequency band of the communication band.

6. The demultiplexing apparatus according to claim 2, further comprising:

a common matching circuit provided between the output terminal and a common node of the signal paths; and

an individual matching circuit provided in each of the signal paths between the common node and the corresponding transmission-reception filter.

8. The demultiplexing apparatus according to claim 6,

wherein phases of a second load impedance in the reception frequency band of each of the communication bands, when viewing the transmission-reception filters from the common node and when plotted in a second Smith chart normalized with respect to impedance of the signal paths, substantially coincide with each other.

10. The demultiplexing apparatus according to claim 8,

wherein each of the individual matching circuits is configured so that an amount of phase rotation of the second load impedance due to the provision of the individual matching circuit is minimized in the second Smith chart.

12. The demultiplexing apparatus according to claim 10,

wherein each individual matching circuit is a high pass filter type matching circuit or a low pass filter type matching circuit.

14. The demultiplexing apparatus according to claim 6,

wherein the common matching circuit and each of the individual matching circuits includes an LC filter of one or more stages, and

wherein the LC filters of each individual matching circuit has more stages than the LC circuit of the common matching circuit.

16. The demultiplexing apparatus according to claim 6,

wherein each of the individual matching circuits is incorporated in the corresponding transmission-reception filter.

18. The demultiplexing apparatus according to claim 6, further comprising:

a switch that is provided between the common matching circuit and the individual matching circuits and that is configured to selectively connect/disconnect at least one of the signal paths, among all of the signal paths, to the common node.

20. The demultiplexing apparatus according to claim 18,

wherein the switch is configured to connect at least two of the signal paths, among all of signal paths, to the common node.