Radar transceiver and antenna sharing method thereof
A radar transceiver is provided. The radar transceiver includes an electrical balance duplexer that is coupled to a transmission node of a transmission path, a reception node of a reception path, and an antenna node and that is configured to isolate the transmission path from the reception path. The electrical balance duplexer includes a hybrid transformer network and a non-tunable balancing impedance. The non-tunable balancing impedance is configured to provide a fixed impedance value that corresponds to an impedance value at the antenna node.
1 . A radar transceiver comprising:
an electrical balance duplexer coupled to a transmission node of a transmission path, a reception node of a reception path, and an antenna node,
wherein the electrical balance duplexer is configured to isolate the transmission path from the reception path,
wherein the electrical balance duplexer comprises a hybrid transformer network and a non-tunable balancing impedance,
wherein the non-tunable balancing impedance is configured to provide a fixed impedance value that is defined corresponding to an impedance value at the antenna node;
a first switch coupled across the non-tunable balancing impedance;
a second switch coupled in-between the non-tunable balancing impedance and a ground potential; and
a switch-control circuit configured to operate the first switch and the second switch.
2 . The radar transceiver according to claim 1 , wherein the radar transceiver further comprises an antenna coupled to the antenna node, wherein the impedance value at the antenna node corresponds to an impedance of the antenna.
3 . The radar transceiver according to claim 1 , wherein the transmission path comprises a signal generator followed by a power amplifier, wherein an output of the power amplifier is coupled to the transmission node, and wherein the reception path comprises a low-noise amplifier followed by a mixer followed by a high-pass filter, and wherein an input of the low-noise amplifier is coupled to the reception node.
4 . The radar transceiver according to claim 3 , wherein the transmission path is configured to generate a transmit signal and further to transmit the transmit signal via the hybrid transformer network and the antenna, and wherein the reception path is configured to receive, via the antenna and the hybrid transformer network, an antenna signal indicative of an incoming echo corresponding to the transmit signal.
5 . The radar transceiver according to claim 4 , wherein the radar transceiver further comprises a delay circuit that is coupled between the signal generator and a local oscillation signal input of the mixer and that is configured to delay the transmit signal, thereby providing a delayed version of the transmit signal to the local oscillation signal input of the mixer, and the delay corresponds to at least one of: (i) a delay of a spillover signal from the transmission path to the reception path through the electrical balance duplexer, or (ii) a delay in the antenna signal.
6 . The radar transceiver according to claim 4 , wherein the signal generator comprises a frequency sweep generator and wherein the transmit signal comprises a swept-frequency signal.
7 . The radar transceiver according to claim 1 , wherein the radar transceiver is configured to be operated in a first operation mode, a second operation mode, and a third operation mode, wherein the switch-control circuit is configured to open the first switch and to close the second switch during the first operation mode, wherein the switch-control circuit is configured to close the first switch and the second switch during the second operation mode, and wherein the switch-control circuit is configured to open the first switch and the second switch during the third operation mode.
8 . The radar transceiver according to claim 1 , wherein the radar transceiver further comprises a third switch coupled in-between the reception node and an input of a low-noise amplifier of the radar transceiver, and the switch-control circuit is further configured to operate the third switch.
9 . The radar transceiver according to claim 8 , wherein the switch-control circuit is configured to:
open the first switch, close the second switch, and close the third switch during a first operation mode,
close the first switch, close the second switch, and close the third switch during a second operation mode, and
open the first switch, open the second switch, and open the third switch during a third operation mode.
10 . The radar transceiver according to claim 1 , wherein the transmission path and the reception path comprise at least one of single-ended transmission lines or single-ended connections.
11 . The radar transceiver according to claim 1 , wherein the transmission path and the reception path comprise at least one of differential transmission lines or differential connections.
12 . The radar transceiver according to claim 1 , wherein the electrical balance duplexer is a wideband electrical balance duplexer.
13 . A radar system comprising a plurality of radar transceivers according to claim 1 , wherein the radar transceivers are arranged in a one-dimensional array or in a two-dimensional array.
14 . The radar system according to claim 13 ,
wherein each of the plurality of radar transceivers is configured to be operated in a first operation mode or in a second operation mode or in a third operation mode, wherein the switch-control circuit of a radar transceiver of the plurality of radar transceivers is configured to close the first switch and the second switch during the second operation mode, and the switch-control circuit is configured to open the first switch and the second switch during the third operation mode.
15 . The radar system according to claim 13 ,
wherein each of the plurality of radar transceivers is configured to be operated in a first operation mode or in a second operation mode or in a third operation mode, a third switch is coupled in-between the reception node of the given radar transceiver and an input of a low-noise amplifier of the given radar transceiver, and the switch-control circuit is further configured to operate the third switch, wherein the switch-control circuit is configured to:
open the first switch, close the second switch, and close the third switch during the first operation mode;
close the first switch, close the second switch, and close the third switch during the second operation mode; and
open the first switch, open the second switch, and open the third switch during the third operation mode.
16 . The radar system according to claim 13 ,
wherein the transmission path of a given radar transceiver of the plurality of radar transceivers comprises a signal generator followed by a power amplifier, wherein an output of the power amplifier is coupled to the transmission node of the given radar transceiver, wherein the reception path of the given radar transceiver comprises a low-noise amplifier followed by a mixer followed by a high-pass filter, and wherein an input of the low-noise amplifier is coupled to the reception node of the given radar transceiver.
17 . The radar system according to claim 16 ,
wherein the transmission path of the given radar transceiver is configured to generate a transmit signal and further to transmit the transmit signal via a hybrid transformer network and an antenna of the given radar transceiver, and wherein the reception path of the given radar transceiver is configured to receive, via the antenna and the hybrid transformer network, an antenna signal indicative of an incoming echo corresponding to the transmit signal.
18 . The radar system according to claim 17 ,
wherein the given radar transceiver further comprises a delay circuit that is coupled between the signal generator and a local oscillation signal input of the mixer and that is configured to delay the transmit signal, thereby providing a delayed version of the transmit signal to the local oscillation signal input of the mixer, and the delay corresponds to at least one of: (i) a delay of a spillover signal from the transmission path of the given radar transceiver to the reception path of the given radar transceiver through the electrical balance duplexer of the given radar transceiver, or (ii) a delay in the antenna signal.
19 . A method for antenna sharing in a radar transceiver including a first switch, a second switch, and a switch-control unit, the method comprising:
operating an electrical balance duplexer to isolate a transmission path from a reception path, wherein the electrical balance duplexer comprises a hybrid transformer network and a non-tunable balancing impedance,
wherein the electrical balance duplexer is coupled to a transmission node of the transmission path, to a reception node of the reception path, and to an antenna node,
wherein the non-tunable balancing impedance is configured to provide a fixed impedance value that is defined corresponding to an impedance value at the antenna node;
coupling the first switch across the non-tunable balancing impedance;
coupling the second switch in-between the non-tunable balancing impedance and a ground potential; and
operating the first switch and the second switch via the switch-control circuit.