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Non-contact Pulse-based Radar with an Excited RF Pulse Generator for Vital-sign Application
(2019-01-01)
Chen, Wei-Hsien
;
Chang, Chia-Hung
;
Kuo, Chien-Nan
;
Hsu, Chia-Chin
;
電子工程學系及電子研究所
This paper presents a pulse-based investigation to generate a serial of sensing pulses for probing the reciprocal movements of heartbeat and chest, respectively. An excited self-contained RF pulse generator with digital assisted controller is used for pulse shaping and performing nanosecond sensing pulses. In addition, the generator is implemented by a common source field-controlled transistor and a contour circuit by micro-strip line. Hence, in this paper, probing pulses and receives the echoes from the investigated subject back and forth by the whole sensing radar based on the monostatic antenna system. The demodulator is utilized to perform the multiplication of the reference probing waves and the return echoes delayed by the time interval between the emitted signal and reflected waves back to the radar module. The following analog baseband processing circuits with 3-stage topology for further amplifying and filtering the received physiological information help to increase the overall signal-to-noise ratio (SNR). The measured results demonstrate that the radiated RF pulses and vital signs are expected.
Long-Term Performance Studies of a LoRaWAN-based PM2.5 Application on Campus
(2018-01-01)
Wang, Shie-Yuan
;
Zou, Ji-Jhe
;
Chen, Yo-Ru
;
Hsu, Chun-Chia
;
Cheng, Yu-Hsiang
Recently, LoRa/LoRaWAN has been proposed as a promising LPWAN technology for Internet-of-Things (IoT) applications. For monitoring the long-term PM2.5 air quality on our campus, starting from February 1 2017, we have set up a LoRaWAN-based PM2.5 air quality monitoring system on our campus. In total, twenty-two PM2.5 sensor devices have been operating at the rooftop of buildings or on the lamp poles since then. Each of these PM2.5 sensor devices uses a LoRaWAN module to send its most recent PM2.5 value to the LoRaWAN gateway every 72 seconds. After being received successfully by the LoRaWAN gateway, the packets carrying these values were stored into a database with their SNR/RSSI information. With the sequence numbers added by our PM2.5 application running on each device, the packets stored in the database provide many important information about the long-term packet loss rate performance of LoRaWAN on campus. In this paper, we process these data to report real long-term performance of LoRaWAN when used on campus.
Vital-Sign Processing Receiver With Clutter Elimination Using Servo Feedback Loop for UWB Pulse Radar System
(2020-01-01)
Chang, Chia-Hung
;
Chen, Wei-Hsien
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
This brief presents a vital-sign processing circuit for simultaneous dc/near-dc elimination and out-of-band interference rejection without any digital signal processing or algorithm assistance for the ultrawideband (UWB) pulse-based radar system. An intrinsic self-balanced MOS diode (SBMD) was proposed as a stable and balanced pseudo resistor applied under a servo feedback loop in a vital-sign receiver of the sensing radar to perform as a high-pass filter (HPF) with an ultralow corner frequency lower than 0.5 Hz for removing undesired clutters of the reflected signals and input dc-offset voltages from innate circuit offsets. A third-order switched-capacitor (SC) Chebyshev low-pass filter (LPF) with leap-frog topology as the subsequent stage was adopted to suppress the out-band noises, thereby establishing an integrated vital-sign processing circuit with bandpass frequency response and incorporating it into a radar module to verify its viability.
A charge accumulation-free voltage-controlled functional electrical stimulator with bi-phasic sinusoidal stimulation
(2019-11-01)
Chen, Wei-Hsien
;
Chang, Chia-Hung
;
Shih, Horng-Yuan
;
Chiu, Tzai-Wen
;
Kuo, Chien-Nan
This paper presents a charge accumulation-free voltage-controlled (VC) bi-phasic sinusoidal functional electrical stimulator (FES) for bioelectronic application. Traditionally, constant current (CC) pulse-shaped FESs with active or passive charge balancers are used to compensate for accumulated charges arise from process, voltage and temperature (PVT) variation as a result of long-term stimulation. Unlike the CC pulse-shaped FES, the VC sinusoidal-shaped FES is adopted here to avoid charge accumulation over time. The charge balancer is not required, substantially reducing system complexity and the chip area of the FES. To demonstrate the feasibility of concept, in this paper, four channels of VC bi-phasic sinusoidal-shaped FESs are integrated with the bio-potential recording circuit to compare with four channels of CC bi-phasic pulse-shaped FESs that are integrated with the same neural recording system for comparison. Measurements indicate an absence of charge accumulation as a result of the VC FESs. In addition, here we adopt the sinusoidal stimulation to reduce transient effects on tissue in comparison to a pulse-shaped method. The bio-potential activities of a cockroach leg that is stimulated for 50 s by the proposed bi-phasic sinusoidal stimulation are recorded. The measured bio-potential activities of a cockroach leg show that no stimulation-evoked leg movement occurs under stimulation by the sinusoidal waveform.
On Investigation of Near-field Antenna for Pulse based Vital-sign Monitoring Application
(2018-01-01)
Chang, Chia-Hung
;
Hung, Wei-Ping
;
電信工程研究所
;
Institute of Communications Engineering
This paper presents a pulsed-based vital-sign monitoring system using a comb-shaped antenna for wearable application. Two prototypes of near-field antenna are designed to investigate the performance of the received physiological signal on the wrist artery of a subject. The real-time, non-contact, and compact sensing module is analyzed, designed, and implemented.
Performance of LoRa-based IoT Applications on Campus
(2017-01-01)
Wang, Shie-Yuan
;
Chen, Yo-Ru
;
Chen, Tzu-Yang
;
Chang, Chia-Hung
;
Cheng, Yu-Hsiang
To promote smart campus, National Chiao Tung University is deploying several location-based IoT applications based on wireless communications technologies including LoRa and NB-IoT. The applications are indoor/outdoor environment conditions monitoring (such as PM2.5, temperature, and humidity), emergency buttons, and so on. This paper uses PM2.5 measurement application as an example to present the performance of LoRa when it is used on campus. We investigated the LoRa transmission performance from LoRa end-devices to the LoRa gateway. We show how packet losses were affected by the distance between the end-device and the gateway, the transmit power, the payload length, the antenna angle, the time of day, and the weather conditions. The pattern of LoRa packet losses were also measured and we found that in our long-term PM2.5 monitoring application, more than 99% of LoRa packet losses occurred with three or less consecutive packet losses.
Application of Smart Appliances to Wireless Area Network and Module Development
(2017-01-01)
Hung, Wei-Ping
;
Lee, Tsern-Huei
;
Chang, Chia-Hung
;
電信工程研究所
;
Institute of Communications Engineering
In this paper, we implement the Wi-Fi hardware architecture. The core chip designed by the MediaTek Corporation is used to develop its peripheral circuits. The chip supports USB Type and can control the lighting circuit through the APP on the mobile phone, so as to simulate the switch of household electrical appliances. In the future, consumers can purchase home appliances with built-in communication modules and integrate them with the Home Energy Management System (HEMS), which can be used to control wireless energy-saving.
V-band Flip-Chip pHEMT Balanced Power Amplifier with CPWG-MS-CPWG Topology and CPWG Lange Couplers
(2017-01-01)
Chang, Wei-Ling
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Su, Jen-Yi
;
Meng, Chinchun
;
Chang, Chia-Hung
;
Huang, Guo-Wei
A V-band balanced two-stage power amplifier MMICs with Lange couplers is demonstrated using 0.15 mu m GaAs pHEMT technology in this paper. A CPWG-MS-CPWG topology with via holes at the transistors as the transition between coplanar waveguide with backside ground (CPWG) and microstrip (MS) is employed for the two-stage amplifier. CPWG is applied to realize the flip-chip transition interface for both input and output ports of the amplifier and inter-stage MS matching has the advantage of small size. The structure parameters of the CPWG Lange coupler and matching network are designed and optimized for power combining. Finally, a 60-GHz balanced two-stage power amplifier using a CPWG-MS-CPWG structure delivers the small signal gain of 18 dB, OP1dB of 12 dBm and P-sat of 15 dBm.
Non-invasive Detection of Object by UWB Radar
(2017-01-01)
Hung, Wei-Ping
;
Lee, Tsern-Huei
;
Chang, Chia-Hung
;
電信工程研究所
;
Institute of Communications Engineering
The use of UWB system front-end matching with the antenna from the VCO side adjustment, the key in the vicinity of the VCO circuit matching adjustment; because eight antennas, each antenna will have some slight differences in matching, resulting in the received DC value is not Will be in the same level, and the switch circuit in the switch antenna, it will allow a peak level (about 100ms), and switch the antenna when switching about 420ms similar to 480ms or so. In order to improve the above problem, when switching to the antenna, a variable of the calculation time is used as the current switching antenna, and the time of the switching of the antenna is changed, The time at the time of the operation is changed by 60 ms due to the switching time. As mentioned above, the calculated time will not be a constant value. Therefore, the remainder is divided by a constant, since the value of the first 100 ms can not be used, So to take the signal between 200ms similar to 400ms in order to correctly reflect the antenna front of the object of the reflected signal; After modifying the above problem, the software interface can detect whether there are metal objects in front of the antenna, and L-shaped steel plate to do experiments, The results show that the L pattern can be displayed on the screen; follow-up planning of a variety of different materials of the metal material corresponding to the DC level, and the use of statistical methods can be further accurate analysis of different metal types, the future can be extended application of Homeland Security Survey, Metal material detection and other areas
Real-Time and Noncontact Impulse Radio Radar System for mu m Movement Accuracy and Vital-Sign Monitoring Applications
(2017-04-15)
Hung, Wei-Ping
;
Chang, Chia-Hung
;
Lee, Tsern-Huei
;
電信工程研究所
;
Institute of Communications Engineering
In this paper, a real-time, contactless pulse-based ultra-wideband (UWB) radar sensor was used to precisely detect the movement of the robotic arm, heartbeats, and respiration activities. To increase the object tracking resolution, an algorithm using adaptive and digitalized post-calibration techniques were proposed and tested. Both the radiated and reflected analog pulses were converted to digital signals by a low-noise comparator and its buffer for the time interval and distance detection. Moreover, the dynamic and calibrated tracking mechanism was incorporated into the algorithm for improving tracking accuracy and to continuously localize an object's vibration. The measured performance revealed that the proposed method successfully achieved mu m movement precision, thus providing its excellent tracking ability. We performed three different experimental tests to demonstrate the UWB radar's viability. First, the radar was employed to detect the undesired structural vibration of a delta robotic arm, which was subjected to high acceleration and structural flexibility. The measured results indicated that the accuracy of 100 mu m can be achieved at a 10 Hz vibration frequency. Next, the apnea alarm was tested, which included an embedded sensitive sensor in the smart mattress in order to execute long-term physiological monitoring. The apnea was mitigated by auto-adjusting the patient's sleeping posture on the mattress when the UWB sensor detected the apnea condition. The final experiment using the radar sensor was to monitor human vital signs, such as heart and breathing rates, simultaneously. In comparison with a commercial electrocardiography instrument, this radar sensor measured 73.2 bpm with only 1.2% deviation. Our results shown that the contactless UWB sensor performs superbly and is well-suited for monitoring physiological parameters.

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