Antenna switching circuits for radio telephones
First Claim
1. Antenna switching circuitry for use in a radio telephone of a type that includes a first transceiver operable in a first frequency band and a second transceiver operable in a second frequency band, the radio telephone further comprising a first antenna port and a second antenna port, said antenna switching circuitry comprising:
- a first pair of transmission lines (L1 and L4) each having a first node coupled to an input/output port of said first transceiver, a second node of L1 being switchably coupled to said first antenna port and a second node of L4 being switchably coupled to said second antenna port; and
a second pair of transmission lines (L2 and L3) each having a first node coupled to an input/output port of said second transceiver, a second node of L2 being switchably coupled to said first antenna port and a second node of L3 being switchably coupled to said second antenna port;
whereinwhen the second node of L1 is coupled to said first antenna port, the second node of both L2 and L4 is open circuited and the second node of L3 is coupled to said second antenna port; and
whereinwhen the second node of L2 is coupled to said first antenna port, the second node of both L1 and L3 is open circuited and the second node of L4 is coupled to said second antenna port.
1 Assignment
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Accused Products
Abstract
Disclosed are various embodiments of circuitry for coupling first and second transceivers of a dual band radio telephone to integral and external antennas. The circuitry uses impedance matching lengths of transmission lines and switches arranged to provide a minimum insertion loss. Also disclosed is an embodiment for use with a single band radio telephone, such as a digital TDMA radio telephone that either transmits or receives at any given time. Also disclosed is an antenna switching arrangement for a dual band phone that eliminates a requirement for duplexers.
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Citations
17 Claims
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1. Antenna switching circuitry for use in a radio telephone of a type that includes a first transceiver operable in a first frequency band and a second transceiver operable in a second frequency band, the radio telephone further comprising a first antenna port and a second antenna port, said antenna switching circuitry comprising:
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a first pair of transmission lines (L1 and L4) each having a first node coupled to an input/output port of said first transceiver, a second node of L1 being switchably coupled to said first antenna port and a second node of L4 being switchably coupled to said second antenna port; and a second pair of transmission lines (L2 and L3) each having a first node coupled to an input/output port of said second transceiver, a second node of L2 being switchably coupled to said first antenna port and a second node of L3 being switchably coupled to said second antenna port;
whereinwhen the second node of L1 is coupled to said first antenna port, the second node of both L2 and L4 is open circuited and the second node of L3 is coupled to said second antenna port; and
whereinwhen the second node of L2 is coupled to said first antenna port, the second node of both L1 and L3 is open circuited and the second node of L4 is coupled to said second antenna port. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. Antenna switching circuitry for use in a radio telephone of a type that includes a first transceiver operable in a first frequency band and a second transceiver operable in a second frequency band, the radio telephone further comprising a first antenna port and a second antenna port, said antenna switching circuitry comprising:
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a first pair of transmission lines (L1 and L2) each having a first node coupled to said first antenna port, a second node of L1 being switchably coupled to an input/output port of said first transceiver and a second node of L2 being switchably coupled to an input/output node of said second transceiver; and a second pair of transmission lines (L3 and L4) each having a first node coupled to said second antenna port, a second node of L3 being switchably coupled to said input/output port of said first transceiver and a second node of L4 being switchably coupled to said input/output node of said second transceiver;
whereinwhen the second node of L1 is coupled to said input/output port of said first transceiver, the second node of both L2 and L3 is open circuited and the second node of L4 is coupled to said input/output port of said second transceiver; and
whereinwhen the second node of L2 is coupled to said input/output port of said second transceiver, the second node of both L1 and L4 is open circuited and the second node of L3 is coupled to said input/output port of said first transceiver. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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Specification