Antenna switch module
An antenna switch module between several radio-frequency transmit and/or receive paths including, between a common terminal on the antenna side and an access capacitor specific to each path, at least one diode, the number of diodes directly connected to the common terminal being odd and the number of diodes having their cathode on the common terminal side being equal, with a difference of one, to the number of diodes having their anode on the common terminal side.
1. An antenna switch module comprising several radio-frequency paths, each of the radio-frequency paths comprising a signal path between a common terminal on an antenna side and a transmit terminal or a receive terminal and further comprising at least one diode in the signal path between the common terminal and the transmit terminal or the receive terminal, wherein the number of said diodes directly connected to said common terminal is odd, the number of said diodes having their cathode on the common terminal side being equal, with a difference of one, to the number of said diodes having their anode on the common terminal side.
2. The switch of claim 1 , wherein the diodes are distributed so that, when a transmit path is selected, the number of diodes of the other paths having their anodes connected to the common terminal is equal to the number of diodes of the other paths having their cathodes connected to the common terminal.
3. The switch of claim 2 , wherein each bias circuit selects one voltage out of two.
4. The switch of claim 3 , wherein the two bias voltages are identical for all paths.
5. The switch of claim 3 , wherein the bias voltage of the diodes having their anodes connected to the common terminal is greater than the bias voltage of the diodes having their cathodes connected to the common terminal.
6. The switch of claim 1 , wherein each path comprises a circuit for biasing the diode which is associated thereto to only bias it forward when this path is selected.
7. The switch of claim 6 , wherein a bias circuit connects the common terminal to a voltage compatible with the conduction of the diode of the selected path.
8. The switch of claim 1 , wherein at least one of said diodes connected to said common terminal is common to a first group of paths, each path in the group comprising a diode which is specific thereto between its access terminal and said common diode.
9. An antenna switch module comprising:
a common terminal on an antenna side of the antenna switch module; and
a plurality of radio-frequency paths coupled to the common terminal, each of the radio-frequency paths comprising a transmit signal path or a receive signal path and including at least one diode in the radio-frequency path between the common terminal and a transmit terminal or a receive terminal, wherein a number of said diodes directly connected to the common terminal is odd and wherein a number of said diodes directly connected to the common terminal and having their cathode on a common terminal side differs by one from a number of said diodes directly connected to the common terminal and having their anode on the common terminal side.
10. An antenna switch module as defined in claim 9 , wherein the diodes are configured such that when a transmit signal path is selected, the number of diodes of other paths having their anodes connected to the common terminal is equal to the number of diodes of other paths having their cathodes connected to the common terminal.
11. An antenna switch module as defined in claim 9 , wherein each radio-frequency path includes a bias circuit to forward bias the diode in response to a selection signal.
12. An antenna switch module as defined in claim 11 , wherein the bias circuit connects the common terminal to a voltage suitable for conduction of the diode of the selected path.
13. An antenna switch module as defined in claim 9 , wherein at least one of the diodes connected to the common terminal is common to a group of radio-frequency paths.