Radar system having a photonics-based signal generator
The present application relates to radio detection and ranging (radar) systems and, in particular, to a radar system having a photonics-based signal generator. Such a radar system comprises a stepped-frequency optical signal generator, an optical-to-electrical converter, and a transmitter. The stepped-frequency optical signal generator is configured for converting an optical signal into a stepped-frequency optical signal. The optical-to-electrical converter for converting the stepped-frequency optical signal into a stepped-frequency electrical signal. The transmitter for transmitting a microwave signal based on the stepped-frequency electrical signal.
1 . A radar system comprising:
a stepped-frequency optical signal generator configured for converting a first optical signal into a stepped-frequency optical signal;
a second light source configured for transmitting a second optical signal;
an X-junction optical beam splitting device configured for receiving the stepped-frequency optical signal and the second optical signal and for combining the received signals into a reference signal;
an optical-to-electrical converter for converting the reference signal into a stepped-frequency electrical signal; and
a transmitter for transmitting a microwave signal based on the stepped-frequency electrical signal.
2 . The radar system of claim 1 , wherein the stepped-frequency optical signal generator comprises:
an optical switch for modulating the first optical signal into a pulse-shaped optical signal, the pulse-shaped optical signal having a pulse; and
an optical frequency shifting loop for converting the pulse-shaped optical signal into the stepped-frequency optical signal.
3 . The radar system of claim 2 , wherein the optical frequency shifting loop comprises a frequency shifter to shift a frequency of the pulse.
4 . The radar system of claim 2 , wherein the pulse-shaped optical signal iteratively travels through the optical frequency shifting loop, wherein each iteration through the optical frequency shifting loop shifts the frequency of the pulse by a frequency shift.
5 . The radar system of claim 1 , further comprising a first light source for generating the first optical signal.
6 . The radar system of claim 1 , further comprising:
a receiver for receiving the transmitted microwave signal that is reflected by an object;
an electro-optic modulator for modulating the stepped-frequency optical signal with the received microwave signal to generate a demodulated optical signal; and
an optical-to-electrical converter for converting the demodulated optical signal into an electrical signal, wherein the electrical signal is used to extract information regarding the object.
7 . The radar system of claim 6 , further comprising:
a filter for filtering the demodulated optical signal.
8 . The radar system of claim 6 , wherein the second optical signal in combination with the first optical signal modify a carrier frequency of the radar system.
9 . The radar system of claim 1 , wherein the radar system detects vital signs of a target, wherein the vital signals comprise respiration rate, heart rate, and blood pressure.
10 . The radar system of claim 3 , wherein the pulse-shaped optical signal iteratively travels through the optical frequency shifting loop, wherein each iteration through the optical frequency shifting loop shifts the frequency of the pulse by a frequency shift.
11 . The radar system of claim 2 , further comprising a first light source for generating the first optical signal.
12 . The radar system of claim 3 , further comprising a first light source for generating the first optical signal.
13 . The radar system of claim 4 , further comprising a first light source for generating the first optical signal.
14 . The radar system of claim 2 , further comprising:
a receiver for receiving the transmitted microwave signal that is reflected by an object;
an electro-optic modulator for modulating the reference signal with the received microwave signal to generate a demodulated optical signal; and
an optical-to-electrical converter for converting the demodulated optical signal into an electrical signal, wherein the electrical signal is used to extract information regarding the object.
15 . The radar system of claim 3 , further comprising:
a receiver for receiving the transmitted microwave signal that is reflected by an object;
an electro-optic modulator for modulating the reference signal with the received microwave signal to generate a demodulated optical signal; and
an optical-to-electrical converter for converting the demodulated optical signal into an electrical signal, wherein the electrical signal is used to extract information regarding the object.
16 . The radar system of claim 4 , further comprising:
a receiver for receiving the transmitted microwave signal that is reflected by an object;
an electro-optic modulator for modulating the reference signal with the received microwave signal to generate a demodulated optical signal; and
an optical-to-electrical converter for converting the demodulated optical signal into an electrical signal, wherein the electrical signal is used to extract information regarding the object.
17 . The radar system of claim 5 , further comprising:
a receiver for receiving the transmitted microwave signal that is reflected by an object;
an electro-optic modulator for modulating the reference signal with the received microwave signal to generate a demodulated optical signal; and
an optical-to-electrical converter for converting the demodulated optical signal into an electrical signal, wherein the electrical signal is used to extract information regarding the object.
18 . The radar system of claim 7 , wherein the second optical signal in combination with the first optical signal modify a carrier frequency of the radar system.