3-frequency branching circuit, branching circuit, and radio communication device

A branching circuit having a filter function of passing a transmitting frequency band and a receiving frequency band in each of a first to Nth frequency bands, comprising:

• first and second internal terminals;
• an antenna terminal of connecting to an antenna;
• branching means having a first filter of passing n+1-th (2≦n≦N−1) to Nth frequency bands between said first internal terminal and said antenna terminal and a second filter of passing the first to said nth frequency bands between said second internal terminal and the antenna terminal;
• a first switching circuit, connected to said first internal terminal, of switching between the transmitting frequency bands and the receiving frequency bands of said n+1-th to Nth frequency bands;
• a second switching circuit, connected to said second internal terminal, of switching between the transmitting frequency bands of said first frequency band and said second to nth frequency bands and the receiving frequency bands of said second to the nth frequency bands;
• and
• a duplexer of branching the transmitting frequency band and the receiving frequency band of said first frequency band.

A 3-frequency branching circuit having a filter function of passing a transmitting frequency band and a receiving frequency band in each of first, second and third frequency bands, comprising:

• first, second, third and fourth internal terminals;
• an antenna terminal of connecting to an antenna;
• branching means having a first filter of passing said third frequency band between said first internal terminal and said antenna terminal and a second filter of passing said first and second frequency bands between said second internal terminal and said antenna terminal;
• a first switching circuit, connected to said first internal terminal, of switching between the transmitting frequency band and the receiving frequency band of said third frequency band;
• a second switching circuit, connected to said second internal terminal, of switching and transmitting the second frequency band to the third internal terminal and the first frequency band to the fourth internal terminal;
• a third switching circuit, connected to said third internal terminal, of switching between the transmitting frequency band and the receiving frequency band of said second transmitting frequency band;
• and
• a duplexer, connected to said fourth internal terminal, of branching the transmitting frequency band and the receiving frequency band of said first frequency band.

A branching circuit having a filter function of passing a transmitting frequency band and a receiving frequency band in each of first to Nth frequency bands, comprising:

• first, second, third and fourth internal terminals;
• an antenna terminal of connecting to an antenna;
• branching means having a first filter of passing said n+1-th (2≦n≦N−1) to Nth frequency bands between said first internal terminal and said antenna terminal and a second filter of passing said first to said nth frequency bands between said second internal terminal and the antenna terminal;
• a first switching circuit, connected to said first internal terminal, of switching among the frequency bands of said n+1-th to Nth frequency bands;
• a second switching circuit, connected to said second internal terminal, of switching and transmitting the second to n-th frequency bands to said third internal terminal and the first frequency band to said fourth internal terminal;
• a third switching circuit, connected to said third internal terminal, of switching among said second to n-th frequency bands;
• and
• a duplexer, connected to said fourth internal terminal, of branching the transmitting frequency band and the receiving frequency band of said first frequency band.

A 3-frequency branching circuit comprising:

• a duplexer having a filter function of passing a transmitting frequency band and a receiving frequency band in each of first, second and third frequency bands and equipped with first and second internal terminals, an antenna terminal of connecting to an antenna, a first filter of passing transmitting frequency bands of said three frequency bands and receiving frequency bands of said second and third frequency bands between said first internal terminal and said antenna terminal, and a second filter of passing the receiving frequency band of said first frequency band between said second internal terminal and said antenna terminal;
• branching means, connected to said first internal terminal, of branching (1) the transmitting frequency band of said first frequency band, transmitting frequency band of said second frequency band, and receiving frequency band of said second frequency band, (2) the transmitting frequency band of said third frequency band and the receiving frequency band of said third frequency band;
• a first switching circuit of switching between transmitting of said third frequency band and receiving of said third frequency band;
• and
• a second switching circuit of switching between transmitting of said first and second frequency bands and receiving of said second frequency band.

A 3-frequency branching circuit comprising:

• branching means, having a filter function of passing a transmitting frequency band and a receiving frequency band in each of first, second and third frequency bands, of branching (1) the transmitting frequency band and receiving frequency band of said third frequency band, (2) the transmitting frequency band of said first and second frequency bands and the receiving frequency band of said first and second frequency bands, having first and second internal terminals, an antenna terminal of connecting to an antenna, a first filter of passing the transmitting frequency band and receiving frequency band of the third frequency band between said first internal terminal and said antenna terminal and a second filter of passing the transmitting frequency band of said first and second frequency bands and the receiving frequency band of said first and second frequency bands between said second internal terminal and said antenna terminal;
• a first switching circuit, connected to said first internal terminal, of switching between transmitting of said third frequency band and receiving of said third frequency band;
• a duplexer, connected to said second internal terminal, having third and fourth internal terminals, a third filter of passing the transmitting frequency band of said first and second frequency bands and the receiving frequency band of said second frequency band between said third internal terminal and said second internal terminal, and a fourth filter of passing the receiving frequency band of said first frequency band between said fourth internal terminal and said second internal terminal;
• and
• a second switching circuit, connected to said third internal terminal, of switching between the transmitting frequency band of said first and second frequency bands and the receiving frequency band of said second frequency band.

A 3-frequency branching circuit comprising:

• a duplexer having a filter function of passing a transmitting frequency band and a receiving frequency band in each of first, second and third frequency bands and equipped with first, second and third internal terminals, an antenna terminal of connecting to an antenna, a first filter of passing a transmitting frequency band and a receiving frequency band of said third frequency band between said first internal terminal and said antenna terminal, a second filter of passing the transmitting frequency band of said first and second frequency bands and the receiving frequency band of said second frequency band between said second internal terminal and said antenna terminal, and a third filter of passing the receiving frequency band of said first frequency band between said third internal terminal and said antenna terminal;
• a first switching circuit, connected to said first internal terminal, of switching between the transmitting frequency band and the receiving frequency band of said third frequency band;
• and
• a second switching circuit, connected to said second internal terminal, of switching between the transmitting frequency band of said first and second frequency bands and the receiving frequency band of said second frequency band.

A branching circuit comprising:

• first branching means having a filter function of passing a transmitting frequency band and a receiving frequency band in each of first to Nth frequency bands, and equipped with first and second internal terminals and an antenna terminal of connecting to an antenna;
• and
• second branching means having a filter function of passing the transmitting frequency band and the receiving frequency band in each of first to N−1-th frequency bands, and equipped with third to k-th internal terminals and a connection terminal of connecting to. said second internal terminal,
• wherein said first internal terminal is a terminal of inputting and outputting the transmitting frequency bands and the receiving frequency bands of said N-th frequency bands;
• said second internal terminal is a terminal of inputting and outputting the transmitting frequency band and the receiving frequency band of said first to said N−1-th frequency bands;
• said k-th internal terminal is the terminal of outputting the receiving frequency band of said first frequency band;
• and
• said third internal terminal is the terminal of inputting the transmitting frequency band of said first frequency band and inputting and outputting the transmitting frequency bands and the receiving frequency bands of all or a part of said second to N−1-th frequency bands.

A branching circuit comprising:

• first branching means having a filter function of passing a transmitting frequency band and a receiving frequency band in each of first to Nth frequency bands, and equipped with first and second internal terminals and an antenna terminal of connecting to an antenna;
• and
• second branching means having a filter function of passing the transmitting frequency band and the receiving frequency band in each of first to N−1-th frequency bands, and equipped with third to k-th internal terminals and a connection terminal of connecting to said second internal terminal,
• wherein said first internal terminal is a terminal of inputting and outputting the transmitting frequency band and the receiving frequency band of said N-th frequency band;
• said second internal terminal is the terminal of inputting and outputting the transmitting frequency band and the receiving frequency band of said first to said N−1-th frequency bands;
• said k-th internal terminal is the terminal of inputting the transmitting frequency band of said first frequency band;
• and
• said third internal terminal is the terminal of outputting the receiving frequency band of said first frequency band and inputting and outputting all or a part of the transmitting frequency bands and the receiving frequency bands of said second to N−1-th frequency bands.