Patent ID: 6115585
Filing Date: 2000-09-05
Classification: H01Q,H04B

Abstract:
Antenna switching circuitry for use in a radio telephone of a type that includes a transmitter operable in a first frequency band when transmitting and a receiver operable in a second frequency band when receiving, the radio telephone further comprising a first antenna port and a second antenna port, said antenna switching circuitry comprising:a pair of transmission lines (L1 and L2) each having a first node and a second node, a first node of L2 being coupled to an input port of said receiver and a first node of L1 being coupled to an output port of said transmitter;a first switch having a first switching state for coupling said input port of said receiver to the first antenna port, the first switch further having a second switching state for coupling said output port of said transmitter to the first antenna port through the second mode of L1, wherein in the first switching state of the first switch the second node of L1 is open-circuited; anda second switch operated in phase with the first switch and having a first switching state for coupling said output port of said transmitter to the second antenna port, said second switch further having a second switching state for coupling said input port of said receiver to the second antenna port through the second node of L2, wherein in the first switching state of the second switch the second node of L2 is open-circuited.