US 7,518,469 B2
Multi-band high-frequency circuit, multi-band high-frequency circuit component and multi-band communication apparatus using same
Shigeru Kemmochi, Saitama-ken (Japan); Keisuke Fukamachi, Saitama-ken (Japan); Kazuhiro Hagiwara, Saitama-ken (Japan); and Masayuki Uchida, Tottori-ken (Japan)
Assigned to Hitachi Metals Ltd., Tokyo (Japan)
Appl. No. 10/596,372
PCT Filed Dec. 13, 2004, PCT No. PCT/JP2004/018595
§ 371(c)(1), (2), (4) Date Jun. 09, 2006,
PCT Pub. No. WO2005/057803, PCT Pub. Date Jun. 23, 2005.
Claims priority of application No. 2003-413623 (JP), filed on Dec. 11, 2003.
Prior Publication US 2007/0075803 A1, Apr. 05, 2007
Int. Cl. H01P 5/12 (2006.01); H03H 7/46 (2006.01)
U.S. Cl. 333—126  [333/129; 333/132] 21 Claims
OG exemplary drawing
 
1. A multi-band high-frequency circuit for performing wireless communications among pluralities of communication systems having different communication frequencies, comprising
a high-frequency switch circuit comprising switching elements for switching the connection of pluralities of multi-band antennas to transmitting circuits and receiving circuits;
a first diplexer circuit disposed between said high-frequency switch circuit and said transmitting circuits for branching a high-frequency signal into frequency bands of said communication systems;
a second diplexer circuit disposed between said high-frequency switch circuit and said receiving circuits for branching a high-frequency signal into frequency bands of said communication systems;
said first and second diplexer circuits each comprising a lower-frequency filter circuit and a higher-frequency filter circuit, a bandpass filter circuit being used as said lower-frequency filter circuit in said second diplexer circuit, or disposed between said lower-frequency filter circuit in said second diplexer circuit and said receiving circuit,
said high-frequency switch circuit comprising first to fourth ports, said first port being connected to a first multi-band antenna, said second port being connected to a second multi-band antenna, said third port being connected to said first diplexer circuit, and said fourth port being connected to said second diplexer circuit; and
said switching elements being controlled in an ON or OFF state to select a multi-band antenna for performing wireless communications and to switch the connection of the selected multi-band antenna to said transmitting circuit or said receiving circuit.