High frequency circuit, high frequency part, and communication device

A high-frequency circuit and circuit technology, applied in the direction of circuits, electrical components, electric solid-state devices, etc., can solve the problem that high-frequency circuits cannot fully correspond to IEEE802.11n

CN101438505AInactive Publication Date: 2009-05-20PROTERIAL LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2009-05-20
Estimated Expiration
Not applicable · inactive patent

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Abstract

A high-frequency circuit for wireless communications selectively using a first frequency band and a second frequency band lower than the first frequency band, comprising an antenna terminal; first and second transmission terminals to which transmitting signals in the first and second frequency bands are input; first and second receiving terminals from which received signals in the first and second frequency bands are output; a diplexer circuit for branching a first-frequency-band-signal path and a second-frequency-band-signal path; a switch circuit for switching a path for a transmitting signal and a path for a received signal; a low-noise amplifier circuit disposed between the switch circuit and the second receiving terminal for amplifying a received signal in the second frequency band; and first and second filter circuits disposed between the antenna terminal and the low-noise amplifier circuit in this order from the antenna terminal, both filter circuits passing a received signal in the second frequency band but blocking a frequency band lower than the second frequency band, and the band blocked by the first filter circuit being lower than the band blocked by the second filter circuit.
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Description

technical field

[0001] The present invention relates to a high-frequency circuit that can be shared by at least two communication systems, a high-frequency component having such a high-frequency circuit, and a communication device using the high-frequency component. Background technique

[0002] Currently, data communication based on wireless LAN represented by the IEEE802.11 standard is widely used, and is used in peripheral devices of PCs such as personal computers (PCs), printers or hard disks, and broadband routers, FAX, refrigerators, and standard-definition televisions (SDTVs). ), high-definition television (HDTV), digital camera, digital video camera, mobile phone and other electronic equipment, and electronic and electrical equipment such as wireless communication mechanisms in automobiles and aircraft.

[0003] As a wireless LAN standard, IEEE802.11a adopts OFDM (Orthogonal Frequency Division Multiples: Orthogonal Frequency Division Multiplexing) modulation method i...

Examples

no. 1 approach

[0134] (A) High frequency circuit

[0135] (1) Overall structure

[0136] FIG. 1 shows a high-frequency circuit in the first embodiment of the present invention that can be commonly used in two communication systems of 2.4GHz band wireless LAN (IEEE802.11b and / or IEEE802.11g) and 5GHz band wireless LAN (IEEE802.11a) . This high-frequency circuit has: a switch circuit (SPDT) 101 connected to the antenna terminal Ant connected to a multi-band antenna, a first demultiplexer circuit (DIP) 103 connected to the transmission path side of the switch circuit (SPDT) 101, and a A high-pass filter circuit (HPF) 118 as a first filter is provided between the terminal Ant and the switch circuit 101 . The first demultiplexing circuit 103 is composed of the following circuits: a low-frequency side filter circuit that passes a transmission signal of a wireless LAN in a 2.4 GHz band but attenuates a transmission signal of a wireless LAN in a 5 GHz band; and a circuit that attenuates a transmis...

no. 3 approach

[0211] (A) High frequency circuit

[0212] FIG. 30 shows another embodiment of the present invention that can be used in two communication systems of a 5GHz band wireless LAN (IEEE802.11a) and a 2.4GHz band wireless LAN (IEEE802.11b and / or IEEE802.11g). high frequency circuit. This high-frequency circuit includes a high-pass filter circuit (HPF) 318 as a first filter connected to an antenna terminal Ant connected to a multiband antenna, and a demultiplexing circuit (DIP) 301 . The demultiplexing circuit 301 is composed of the following circuits: a high-frequency side filter circuit that attenuates the transmission and reception signals of the 2.4 GHz band wireless LAN through the transmission and reception signals of the 5 GHz band wireless LAN; and the transmission and reception signals of the 2.4 GHz band wireless LAN, It is a low-frequency side filter circuit that attenuates the transmission and reception signals of 5GHz band wireless LAN.

[0213] The first switch circui...