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LU101011B1 - A circuit structure using radio frequency switch to simplify double-sideband doppler radar - Google Patents

A circuit structure using radio frequency switch to simplify double-sideband doppler radar Download PDF

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Publication number
LU101011B1
LU101011B1 LU101011A LU101011A LU101011B1 LU 101011 B1 LU101011 B1 LU 101011B1 LU 101011 A LU101011 A LU 101011A LU 101011 A LU101011 A LU 101011A LU 101011 B1 LU101011 B1 LU 101011B1
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LU
Luxembourg
Prior art keywords
signal
frequency
local oscillator
double
sideband
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LU101011A
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German (de)
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Jianguo Ma
Shaohua Zhou
Zikai Yang
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Univ Tianjin
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/50—Systems of measurement based on relative movement of target
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06—Systems determining position data of a target
    • G01S13/08—Systems for measuring distance only
    • G01S13/32—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
    • G01S13/34—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal
    • G01S13/347—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal using more than one modulation frequency
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/03—Details of HF subsystems specially adapted therefor, e.g. common to transmitter and receiver
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/35—Details of non-pulse systems
    • G01S7/352—Receivers
    • G01S7/354—Extracting wanted echo-signals
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/41—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section
    • G01S7/415—Identification of targets based on measurements of movement associated with the target
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/05—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves
    • A61B5/0507—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves using microwaves or terahertz waves
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/72—Signal processing specially adapted for physiological signals or for diagnostic purposes
    • A61B5/7225—Details of analog processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/03—Details of HF subsystems specially adapted therefor, e.g. common to transmitter and receiver
    • G01S7/034—Duplexers

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  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Physics & Mathematics (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Radar Systems Or Details Thereof (AREA)

Abstract

The present invention discloses a circuit structure using a radio frequency switch to simplify a double-sideband Doppler radar, comprising a receiving antenna (6) and a transmitting antenna (5), wherein the receiving antenna (6) is connected in series with a low noise amplifier (7), a first frequency mixer (8), a bandpass filter (9), an analog-digital converter (10) and a field-programmable gate array (11) in turn; the transmitting antenna (5) is connected in series with a radio frequency switch (4), a power amplifier (3), a power divider (2) and a local oscillator (1) in turn; output of the power divider (2) is divided into two paths: one path is connected to the power amplifier (3), and the other path is connected to the first frequency mixer (8). The present invention reduces the implementation costs of the local oscillator (1) without adjusting the frequency of the local oscillator (1) any more when a distance between the radar and the detected object changes; generates two frequencies in the double-sideband radar structure: one is generated with the local oscillator (1) and the other is implemented with the radio frequency switch (4), so that only one local oscillator (1) is needed, which further reduces the implementation costs of the radar.

Description

A CIRCUIT STRUCTURE USING RADIO FREQUENCY SWITCH TO SIMPLIFY DOUBLE-SIDEBAND DOPPLER RADAR
Field of the Disclosure
The present invention relates to the technical field of Doppler radar, and more specifically to a circuit structure using a radio frequency switch to simplify a double-sideband Doppler radar.
Background of the Disclosure
Microwave Doppler radars, as wireless sensors, are already applied for many years. Aspects in which the microwave Doppler radars are applied most commonly include vehicle speed measurement, weather sensing and location and distance sensing. Since Lin et al. attempted to use microwave Doppler radars to measure physiological movements of a human body for the first time in 1975, microwave Doppler radars, as a kind of noncontact-type vital signs monitoring systems, already attracts too much attention (see reference [1]). Conventional manners of detecting vital sign signals comprise ECG (electrocardiogram), heat or pressure sensor. The manners all require sensors to contact human bodies. Contact with human bodies in a long period of time causes uncomfortable feeling to the patients, and even might affect a measurement precision. Furthermore, the contact type sensors cannot be used with respect to cases such as mental patients and patients with large-area bum, which seriously limits the scope of use of the contact type sensors. Unlike conventional contact type sensors, a very important advantage of the microwave Doppler radar is that it detects vital sign parameters in a non-invasive manner, i.e., it does not need any wearable sensors or cables which might cause uncomfort or affect testing results.
In the past several decades, vital sign detection based on continuous wave Doppler radars are already researched deeply in experimental and actual application environments. Research finds that zero point problem exists in use of a typical continuous wave radar structure of a single-channel frequency mixer (see reference 1 [2]). Regarding the defect, people sequentially proposed a quadrature demodulation structure (see reference [3]) and a transmitting double-sideband-based frequency adjustment technology (see reference [4]) which may effectively solve the zero point problem. As compared with the quadrature demodulation structure, the double-sideband-based frequency adjustment technology needn’t generate a quadrature local oscillation signal, and has a stronger capability of suppressing DC biasing (see reference [5]). However, when a distance between the antenna and a measured object changes, the frequency adjustment technology requires adjustment the frequency of an intermediate-frequency signal. The intermediate-frequency signal is generally implemented using local oscillator or a crystal oscillator. Hence, adjusting the intermediate-frequency signal is relatively complicated in hardware implementation and requires higher costs; furthermore, the frequency adjustment technology requires to perform frequency mixing twice to obtain a baseband signal, which also increases system complexity and hardware costs.
Based on drawbacks in the prior art, it is necessary to propose a simplified double-sideband Doppler radar structure, to overcome drawbacks of conventional double-sideband radar structures.
Summary of the Disclosure
An object of the present invention is to overcome drawbacks in the prior art and provide a circuit structure using a radio frequency switch to simplify a double-sideband Doppler radar, which reduces implementation costs of the local oscillator without adjusting the frequency of the local oscillator any more when a distance between the radar and the detected object changes; generates two frequencies in the double-sideband radar structure: one is generated with the local oscillator and the other is implemented with the radio frequency switch, so that only one local oscillator is needed, which further reduces the implementation costs of the radar; in a receiver portion, frequency mixing of the low-frequency signal is implemented in a digital field, so only one hardware frequency mixer is needed, which further reduces 1 the implementation costs of the radar.
An object of the present invention is achieved with the following technical solution.
The circuit structure using a radio frequency switch to simplify a double-sideband Doppler radar according to the present invention comprises a receiving antenna and a transmitting antenna, and the receiving antenna is connected in series with a low noise amplifier, a first frequency mixer, a bandpass filter, an analog-digital converter and a field-programmable gate array in turn; the transmitting antenna is connected in series with a radio frequency switch, a power amplifier, a power divider and a local oscillator in turn; output of the power divider is divided into two paths: one path is connected to the power amplifier, and the other path is connected to the first frequency mixer .
The field-programmable gate array acts to perform digital frequency reduction, and corresponds to a second frequency mixer and a lowpass filter which are connected to each other.
At a transmitting end, the local oscillator is used to generate a radio frequency signal, and then the power divider is used to averagely divide the radio frequency signal into two paths: one path serves as a transmitted sign, and the other path serves as a local oscillator signal for frequency mixing. The transmitted signal is amplified by the power amplifier, and then modulated by the radio frequency switch, thereby generating a double-sideband signal. The double-sideband signal is transmitted out through the transmitting antenna. At a receiving end, the double-sideband signal received by the receiving antenna is first amplified by the low noise amplifier, and then mixed with the local oscillator signal. The intermediate-frequency signal after the mixing first passes through the bandpass filter to filter away a DC signal and high frequency harmonics, and then the analog-digital converter is used to convert the intermediate frequency signal into a digital signal. Finally, frequency mixing is performed for a second time in the field-programmable gate array to obtain a final baseband signal.
As compared with the prior art, the technical solution of the present invention may bring about the following advantageous effects: (1) The present invention simplifies the structure of the double-sideband radar circuit, reduces the implementation costs of double-sideband Doppler radar, reduces one local oscillator and replaces it with a radio frequency switch at the receiver portion, and reduces one hardware frequency mixer at the receiver portion and implements frequency mixing in a digital field. (2) The present invention simplifies an operation method of the double-sideband Doppler radar, and only needs to use a digital signal to adjust the frequency of the radio frequency switch when the distance between the radar and the detected object changes, which is much simpler than adjusting the frequency of the local oscillator.
Brief Description of Drawings
Fig. 1 is a schematic diagram of a circuit structure using a radio frequency switch to simplify a double-sideband Doppler radar according to the present invention.
Detailed Description of Preferred Embodiments
The present invention will be further described with reference to figures to more clearly illustrate the technical solution of the present invention. Those having ordinary skill in the art may further obtain other figures according to these figures without making any inventive efforts.
The circuit structure using a radio frequency switch to simplify a double-sideband Doppler radar according to the present invention, as shown in Fig. 1, comprises a receiving antenna 6 and a transmitting antenna 5, and the receiving antenna 6 is connected in series with a low noise amplifier 7, a first frequency mixer 8, a bandpass filter 8, an analog-digital converter 10 and a field-programmable gate array 11 in turn. The transmitting antenna 5 is connected in series with a radio frequency switch 4, a power amplifier 3, a power divider 2 and a local oscillator 1 in turn. Output of the power divider 2 is divided into two paths: one path is connected to input of the power amplifier 3, and the other path is connected to input of the first frequency mixer 8. The field-programmable gate array 11 acts to perform digital frequency reduction, and corresponds to a second frequency mixer 12 and a lowpass filter 13 which are connected to each other.
At a transmitting end, the local oscillator 1 is used to generate a radio frequency signal, and then the power divider 2 is used to averagely divide the radio frequency signal into two paths: one path serves as a transmitted sign, and the other path serves as a local oscillator signal for frequency mixing. The transmitted signal is amplified by the power amplifier 3, and then modulated by a radio frequency switch 4, thereby generating a double-sideband signal. The double-sideband signal is transmitted out through the transmitting antenna 5. At a receiving end, the double-sideband signal received by the receiving antenna 6 is first amplified by the low noise amplifier 7, and then mixed with the local oscillator signal. The intermediate-frequency signal after the mixing first passes through the bandpass filter 9 to filter away a DC signal and high frequency harmonics, and then the analog-digital converter 10 is used to convert the intermediate frequency signal into a digital signal. Finally, frequency mixing is performed for a second time in the field-programmable gate array 11 to obtain a final I baseband signal. To minimize residual phase noise of the baseband signal after the mixing, the same crystal oscillator is used to drive the local oscillator 1 and the field-programmable gate array 11.
It is assumed that the local oscillator signal L(t) is represented by Equation (1):
where ƒ is a frequency of the local oscillator signal, and t is time. Assuming a working frequency of the radio frequency switch 4 is 1/2/, it may generate a rectangular wave having a cycle 2/. Fourier expansion is performed for it, and a signal S(t) produced by the radio frequency switch 4 is represented by Equation (2):
(2)
It can be seen from Equation (2) that the amplitude gets smaller starting from the third item, and may be omitted in calculation. Therefore, the signal generated by the radio frequency switch 4 only takes the preceding two items, as shown in Equation (3):
It can be obtained from Equations (1) and (3) that the transmitted signal T(/)is as shown in Equation (4):
(4)
It is assumed that wave length 2=c//j2i=c/(/+l/2/)^2=c/(Fl/2/), wherein c is a propagation speed of the signal. The received signal R(f) that may be obtained according to an Doppler effect is as shown by Equation (5):
(5) where do is a distance between the radar and the detected object, and x(t) is a thoracic movement. The received signal is mixed with the local oscillator signal and passes through the bandpass filter 9 to obtain a processing result 7? i (/) as shown below in Equation (6):
(6)
It is possible to perform analog-digital conversion for the mixed signal 7?i(/), and
mix 7?i(/)and sin(tó//) in a digital field, and go through the lowpass filter 13 to obtain a 1 baseband signal B(Z) as shown by the following Equation (7):
(7)
It is known from document [5] that when a relation shown by the following Equation (8) is satisfied, a measurement result is at a position of an optimal point, namely, the measurement result is the most accurate.
(8)
When the relation shown by Equation (8) is not satisfied, since X\=d(f+1/2/), and Â2=c/(/11/2/), it is possible to satisfy the relation of the optimal point by adjusting a value of /, namely, by adjusting the frequency of the radio frequency switch 4.
Embodiment
Models of elements specifically used in the present invention are described below: the local oscillator 1 employs LTC6948IUFD of Analog Devices, Inc. and is used to generate a 2.14GHz frequency; the power divider 2 employs PD0922J5050S2HF of Anaren; the radio frequency switch 4 employs 4239-52 of pSemi Corporation; the power amplifier 3 employs the one disclosed in reference (see reference [6]); both the transmitting antenna 5 and receiving antenna 6 employ what are disclosed in reference (see reference [7]); the low noise amplifier 7 employs HMC618ALP3ETR of Analog Devices, Inc.; the first frequency mixer 8 and second frequency mixer 12 both employ LT5575EUF of Analog Devices, Inc. The bandpass filter 8 employs 0400LP15A0122 of Johanson Technology Inc.; the analog-digital converter 10 employs ADC07D1520CIYB/NOPB of Texas Instruments Inc.; the field-programmable gate array 11 employs 5CSXFC6D6F31C6N of Intel Corporation.
[References] [ljXiao Y, Lin J, Boric-Lubecke O, et al. A Ka-Band Low Power Doppler Radar System for Remote Detection of Cardiopulmonary Motion[J], 2005, 7:7151-7154.
[2]Droitcour A D, Boric-Lubecke O, Lubecke V M, et al. Range correlation
effect on ISM band I/Q CMOS radar for non-contact vital signs sensing[C], Microwave Symposium Digest, 2003 IEEE MTT-S International. IEEE, 2003:1945-1948 vol.3.
[3] Droitcour A D, Boric-Lubecke O, Lubecke V M, et al. Range correlation and I/Q performance benefits in single-chip silicon Doppler radars for noncontact cardiopulmonary monitoring[J], Microwave Theory & Techniques IEEE Transactions on, 2004, 52(3):838-848.
[4] Li C, Lin J, Xiao Y. Robust Overnight Monitoring of Human Vital Sign by a Non-contact Respiration and Heartbeat Detector [J], 2006, 1:2235-2238.
[5] Xiao Y, Lin J, Boric-Lubecke O, et al. Frequency-tuning technique for remote detection of heartbeat and respiration using low-power double-sideband transmission in the ka-band[J], IEEE Transactions on Microwave Theory & Techniques, 2006, 54(5):2023-2032.
[6] Q. Cheng, H. Fu, S. Zhu and J. Ma, “Two-Stage High-Efficiency Concurrent Dual-Band Harmonic-Tuned Power Amplifier,” IEEE Trans.Microw. Theory Techn., vol. 64, no. 10, pp. 3232-3243, Oct. 2016.
[7] W. An et al., “Low-profile Wideband Slot-loaded Patch Antenna with Multi-Resonant Modes,” IEEE Antennas Wireless Propag. Lett., to be published.
Although functions and operation process of the present invention are described above with reference to figures, the present invention is not limited to the above specific functions and operation process. The above specific implementation modes are only exemplary and unrestrictive. Those having ordinary skill in the art, as suggested or taught by the present invention, may further envisage many forms without departing from the essence of the present invention and extent of protection of claims, and all these forms fall within the extent of protection of the present invention.

Claims (3)

1. Schaltungsaufbau unter Verwendung eines Hochfrequenzschalters zur Vereinfachung eines Doppelseitenband-Doppler-Radars, mit einer Empfangsantenne (6) und einer Sendeantenne (5), dadurch gekennzeichnet, dass die Empfangsantenne (6) mit einem rauscharmen Verstärker (7), einem erster Frequenzmischer (8), einem Bandpassfilter (9), einem Analog-Digital-Wandier (10) und einem feldprogrammierbaren Gate-Array (11) hintereinander in Reihe geschaltet ist, wobei die Sendeantenne (5) mit einem Hochfrequenzschalter (4), einem Leistungsverstärker (3), einem Leistungsteiler (2) und einem lokalen Oszillator (1) hintereinander in Reihe geschaltet ist, und wobei der Ausgang des Leistungsteilers (2) in zwei Pfade unterteilt ist: ein Pfad mit dem Leistungsverstärker (3) verbunden ist, und der andere Pfad mit dem ersten Frequenzmischer (8) verbunden ist.1. Circuit configuration using a high-frequency switch for simplifying a double-sideband Doppler radar, comprising a receiving antenna (6) and a transmitting antenna (5), characterized in that the receiving antenna (6) is connected to a low-noise amplifier (7), a first frequency mixer ( 8), a band-pass filter (9), an analog-to-digital Wandier (10) and a field programmable gate array (11) in series, wherein the transmitting antenna (5) with a high-frequency switch (4), a power amplifier (3 ), a power divider (2) and a local oscillator (1) are connected in series in series, and wherein the output of the power divider (2) is divided into two paths: one path connected to the power amplifier (3) and the other path is connected to the first frequency mixer (8). 2. Schaltungsaufbau unter Verwendung eines Hochfrequenzschalters zur Vereinfachung eines Doppelseitenband-Dopplerradars nach Anspruch 1, dadurch gekennzeichnet, dass das feldprogrammierbare Gate-Array (11) eine digitale Frequenzreduktion durchführt und einem zweiten Frequenzmischer (12) und einem Tiefpassfilter (13) entspricht, die miteinander verbunden sind.2. A circuit structure using a high-frequency switch for simplifying a double-sideband Doppler radar according to claim 1, characterized in that the field-programmable gate array (11) performs a digital frequency reduction and a second frequency mixer (12) and a low-pass filter (13) corresponds to each other are connected. 3. Schaltungsaufbau unter Verwendung eines Hochfrequenzschalters zur Vereinfachung eines Doppelseitenband-Dopplerradars nach Anspruch 1, dadurch gekennzeichnet, dass an einem Sendeende der Lokaloszillator (1) zur Erzeugung eines Radiofrequenzsignals verwendet wird, und anschließend der Leistungsteiler (2) verwendet wird, um das Radioffequenzsignal durchschnittlich in zwei Pfade zu teilen: ein Pfad als ein Sendesignaldient, und der andere Pfad als ein Lokaloszillatorsignal zum Frequenzmischen dient, wobei das Sendesignal dureh den Leistungsverstärker (3) verstärkt und dann dureh den Hochfrequenzschalter (4) moduliert wird, wodurch ein Doppelseitenbandsignal erzeugt wird, wobei das Doppelseitenbandsignal dureh die Sendeantenne (5) ausgesendet wird; und dass an einem Empfangsende das von der Empfangsantenne (6) empfangene Doppelseitenbandsignal zuerst dureh den rauscharmen Verstärker (7) verstärkt und dann mit dem Lokaloszillatorsignal gemischt wird, wobei das Zwischenfrequenzsignal nach dem Durchmischen zuerst das Bandpassfilter (9) durchgeht, um ein Gleichstromsignal und hochfrequente Harmonische wegzufiltem, und dann der Analog-Digital-Wandler (10) verwendet wird, um das Zwischenfrequenzsignal in ein digitales Signal umzuwandeln, und schließlich das Frequenzmischen ein zweites Mai in dem feldprogrammierbaren Gate-Array (11) durchgefuhrt wird, um ein endgültiges Basisbandsignal zu erhalten.3. A circuit structure using a high frequency switch for simplifying a double sideband Doppler radar according to claim 1, characterized in that at a transmitting end of the local oscillator (1) is used to generate a radio frequency signal, and then the power divider (2) is used to average the radio frequency signal dividing into two paths: one path as a transmit signal terminal, and the other path serving as a local oscillator signal for frequency mixing, the transmit signal being amplified by the power amplifier (3) and then modulated by the high frequency switch (4), thereby generating a double sideband signal, wherein the double sideband signal is transmitted through the transmitting antenna (5); and that at a receiving end, the double sideband signal received by the receiving antenna (6) is first amplified by the low noise amplifier (7) and then mixed with the local oscillator signal, the intermediate frequency signal after mixing first passing through the bandpass filter (9) to produce a DC signal and high frequency Harmonic filters, and then the analog-to-digital converter (10) is used to convert the intermediate frequency signal into a digital signal, and finally the frequency mixing is performed a second time in the field programmable gate array (11) to provide a final baseband signal receive.
LU101011A 2018-09-19 2018-11-23 A circuit structure using radio frequency switch to simplify double-sideband doppler radar LU101011B1 (en)

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US12107611B2 (en) 2020-12-11 2024-10-01 Intel Corporation Receiver with reduced noise figure using split LNA and digital combining
CN113030884B (en) * 2021-02-26 2024-03-29 隔空（上海）智能科技有限公司 Doppler radar testing device, testing method and Doppler radar sensor
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