Phased-array doppler radar using an injection-locking technique

Patent metadata

Field	Value
Publication number	US-11808834-B2
Application number	US-202017101040-A
Country	US
Kind code	B2
Filing date	Nov 23, 2020
Priority date	May 18, 2020
Publication date	Nov 7, 2023
Grant date	Nov 7, 2023

Abstract

A phased-array Doppler radar includes a two-way splitter, a transmit antenna, a receive antenna array, an ILO, a demodulation unit and a digital signal processing unit. A reference signal is split by the two-way splitter to the transmit antenna for transmission to targets and the ILO for injection locking. Signals reflected by the targets are received by the receive antenna array as received signals. An injection-locked signal generated by the ILO and the received signals received by the receive antenna array are delivered to the demodulation unit. The received signals are demodulated into baseband I/Q signals by the demodulation unit that uses the injection-locked signal as a local oscillator signal. The baseband I/Q signals are processed by the digital signal processing unit to obtain a digital beamforming pattern.

First claim

What is claimed is:

1. A phased-array Doppler radar comprising:
a two-way splitter configured to receive and split a reference signal into two parts;
a transmit antenna electrically connected to the two-way splitter and configured to transmit one part of the reference signal to an area as a transmitted signal, a plurality of reflected signals is reflected from the area;
a receive antenna array configured to receive the plurality of reflected signals as a plurality of received signals,
wherein the receive antenna array includes a plurality of receive antennas that are configured to receive the plurality of reflected signals as the plurality of received signals, the receive antenna array is configured to be placed horizontally;

an injection-locked oscillator (ILO) electrically connected to the two-way splitter, the ILO is configured to receive and be injected with the other part of the reference signal and configured to generate an injection-locked signal;
a demodulation unit electrically connected to the receive antenna array and the ILO, the demodulation unit is configured to receive the plurality of received signals and the injection-locked signal and configured to demodulate the plurality of received signals into a plurality of baseband I/Q signals by using the injection-locked signal as a local oscillator signal,
wherein the demodulation unit includes a multi-way splitter and a plurality of quadrature demodulators, the multi-way splitter that has a plurality of output ports is electrically connected to the ILO and configured to receive and split the injection-locked signal into a plurality of parts, each of the plurality of quadrature demodulators is electrically connected to one of the plurality of receive antennas and one of the plurality of output ports of the multi-way splitter and configured to receive one of the plurality of received signals and one of the plurality of parts of the injection-locked signal, each of the plurality of quadrature demodulators is further configured to demodulate one of the plurality of received signals using one of the plurality of parts of the injection-locked signal as the local oscillator signal into one of the plurality of baseband I/Q signals; and

a digital signal processing unit electrically connected to the demodulation unit, the digital signal processing unit is configured to receive and process the plurality of baseband I/Q signals to obtain a digital beamforming pattern.

2. The phased-array Doppler radar in accordance with claim 1 , wherein the reference signal is a radio signal that is configured to be delivered from a radio communication device to the two-way splitter via wire or wireless transmission.

3. The phased-array Doppler radar in accordance with claim 1 , wherein the digital beamforming pattern is derived from the following equation:

P
⁡

(
ϕ
)

=

∑

n
=
0

N
-
1

⁢

⁢

S
n

⁢

e

j
⁢

2
⁢
π

λ

⁢

(

nd
r

⁢
cos
⁢

⁢
ϕ

)

where P (ϕ) is the digital beamforming pattern as a function of azimuth angle ϕ, N is the number of the plurality of receive antennas, S n , is the nth one of the plurality of baseband I/O signals in digital complex form, γ is a wavelength of the plurality of received signals, and d r is a distance between two adjacent ones of the plurality of receive antennas.

4. The phased-array Doppler radar in accordance with claim 3 , wherein the digital signal processing unit is configured to extract vital signs of at least one target in the area from the digital beamforming pattern.

5. The phased-array Doppler radar in accordance with claim 1 comprising a plurality of transmit antennas forming a transmit antenna array and a switch, wherein the switch is electrically connected to the two-way splitter to receive one part of the reference signal, the plurality of transmit antennas are electrically connected to the switch to transmit one part of the reference signal via the switch to the area as the transmitted signal. The transmitted signal is transmitted from different ones of the plurality of transmit antennas at different times.

6. The phased-array Doppler radar in accordance with claim 5 , wherein the transmit antenna array is configured to be placed vertically, the digital beamforming pattern is derived from the following equation:

P
⁡

(

θ
,
ϕ

)

=

∑

m
=
0

M
-
1

⁢

⁢

∑

n
=
0

N
-
1

⁢

⁢

S
mn

⁢

e

j
⁢

2
⁢
π

λ

⁢

(

md

Assignees

• National Sun Yat Sen University

Inventors

• Horng Tzyy-Sheng
• Wen Chao-Kai
• Lai Yi-Chen
• Huang Yu-Chi
• Lin Jui-Yen
• Chian De-Ming

Classifications

• G01S13/02 Primary

  Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems · CPC title

• G01S7/4052

  by simulation of echoes · CPC title

• H01Q21/0025

  Modular arrays · CPC title

• G01S7/2886

  using I/Q processing · CPC title

• G01S7/4069

  involving a RF signal injection · CPC title