High-frequency circuit, high-frequency device, and multiband communications apparatus

A high-frequency circuit for use in a multiband wireless apparatus for switching the connection between an antenna and transmission/reception circuits depending on signals for pluralities of communications systems, comprising;

• a single-pole, multi-throw switch circuit comprising FET switch circuits between a common port connected to an antenna-side circuit and pluralities of single ports connected to the transmission/reception circuits, and a first matching circuit connected to said common port;
• said first matching circuit comprising a first inductance element connected in series to a signal path between said antenna and said common port, and a first capacitance element connected to said first inductance element on the antenna side and grounded, said first inductance element making the impedance of said single-pole, multi-throw switch circuit inductive when single port is viewed from said antenna side, and said first capacitance element adjusting impedance matching between said antenna-side circuit and said transmission/reception circuits, wherein pluralities of said communications systems have multi-connection systems including Time Division Multiple Access (TDMA) system and a CDMA Code Division Multiple Access (CDMA) system;
• a bandpass filter connected between a first single port and a first reception circuit for the first communications system of a TDMA system;
• an LC filter circuit connected between a second single port and a first transmission circuit for the first and second communications systems of the TDMA system;
• first duplexers connected between a third single port and a second reception circuit for the second communications system of the TDMA system and the first communications system of the CDMA system, and a second transmission circuit for the first communications system of the CDMA system;
• and
• second duplexers connected between a fourth single port and a third reception circuit for the second communications system of the CDMA system and a third transmission circuit for the second communications system of the CDMA system;
• said second matching circuit being connected to at least one path between said first single port of said single-pole, multi-throw switch circuit and said bandpass filter, between said third single port and said first duplexer, and between said the fourth single port and said second duplexer.

A high-frequency device having in and on an insulating substrate a high-frequency circuit for use in a multiband wireless apparatus for switching the connection between an antenna and transmission/reception circuits depending on signals for pluralities of communications systems,

• said high-frequency circuit comprising a single-pole, multi-throw switch circuit having FET switch circuits between a common port connected to the antenna and pluralities of single ports connected to the transmission/reception circuits, and a first matching circuit connected to said common port, and filter circuits disposed between said single ports and the transmission/reception circuits, at least one of said filter circuits being a bandpass filter;
• said first matching circuit comprising a first inductance element connected in series to a signal path between the antenna and the common port of the single-pole, multi-throw switch circuit, and a first capacitance element connected to said first inductance element on the antenna side and grounded;
• pluralities of filter terminals connected to said filter circuits being aligned on a first side of a bottom surface of a switch device having said single-pole, multi-throw switch circuit;
• filter elements constituting said filter circuits being mounted on an upper surface of said insulating substrate adjacently to said first side of said switch device;
• and
• said switch device and said filter elements being connected via connecting lines formed in said insulating substrate.

A high-frequency device having in and on an insulating substrate a high-frequency circuit for use in a multiband wireless apparatus for switching the connection between an antenna and transmission/reception circuits depending on signals for pluralities of communications systems,

• said high-frequency circuit comprising a single-pole, multi-throw switch circuit having FET switch circuits between a common port connected to the antenna and pluralities of single ports connected to the transmission/reception circuits, a first matching circuit connected to said common port, and filter circuits disposed between said single ports and said transmission/reception circuits, at least one of said filter circuits being a bandpass filter,
• said first matching circuit comprising a first inductance element connected in series to a signal path between said antenna and said common port, and a first capacitance element connected to said first inductance element on the antenna side and grounded;
• pluralities of filter terminals connected to said filter circuits being aligned on a bottom surface of a switch device having said single-pole, multi-throw switch circuit, and an antenna terminal connected to said antenna being formed on said bottom surface;
• said switch device, filter elements constituting said filter circuits and the first inductance element constituting said first matching circuit being adjacently mounted on an upper surface of said insulating substrate;
• and
• said switch device and said filter element, and said switch device and said first inductance element being respectively connected via connecting lines formed in said insulating substrate such that the connecting lines do not overlap each other in a lamination direction.

A high-frequency device having in and on an insulating substrate a high-frequency circuit for use in a multiband wireless apparatus for switching the connection between an antenna and transmission/reception circuits depending on signals for pluralities of communications systems,

• said high-frequency circuit comprising a single-pole, multi-throw switch circuit having FET switch circuits between a common port connected to the antenna and pluralities of single ports connected to the transmission/reception circuits, a first matching circuit connected to said common port, and filter circuits disposed between said single ports and the transmission/reception circuits, at least one of said filter circuits being a bandpass filter;
• said first matching circuit comprising a first inductance element connected in series to a signal path between the antenna and the common port of said single-pole, multi-throw switch circuit, and a first capacitance element connected to said first inductance element on the antenna side and grounded;
• pluralities of filter terminals connected to said filter circuits being aligned on a bottom surface of a switch device having said single-pole, multi-throw switch circuit, and an antenna terminal connected to said antenna being formed on said bottom surface;
• said switch device, filter elements constituting said filter circuits and the first inductance element constituting said first matching circuit being adjacently mounted on an upper surface of said insulating substrate;
• said switch device and said filter element, and said switch device and said first inductance element being respectively connected via connecting lines formed in the multi-layer insulating substrate;
• and
• layers having ground electrodes being disposed between said connecting lines formed on different layers.