氨气是畜禽场景中的主要有害气体之一,针对有源传感器不适于电路有线连接受限的畜禽场景问题,该研究基于高频电磁仿真软件(high frequency structure simulator,HFSS)设计了无源传感器仿真模型,选择聚酰亚胺(polyimide,PI)作为基板材料...氨气是畜禽场景中的主要有害气体之一,针对有源传感器不适于电路有线连接受限的畜禽场景问题,该研究基于高频电磁仿真软件(high frequency structure simulator,HFSS)设计了无源传感器仿真模型,选择聚酰亚胺(polyimide,PI)作为基板材料,采用丝网印刷技术研制了基于射频识别(radio frequency identification,RFID)原理的无源氨气传感标签。通过对氨气无源检测原理的解析,选择了具有高表面积的碳纳米管作为氨气敏感材料,推导了通过测量射频接收功率变化实现无源检测的数学模型;考虑谐振频率的动态调整,无源RFID传感标签采用开口间隙可调的裂环谐振器结构,通过分析传输系数的变化对RFID传感标签的检测过程进行模拟;搭建了用于实验室和畜禽场景氨气检测的射频测试系统,围绕功率反射系数、谐振频率、传输系数开展测试分析。试验结果表明,该标签检测效率易受到到二氧化碳、温湿度因素的影响,由于人工切割、基板变形、环境干扰等因素,实物标签的谐振频率与2.4 GHz的仿真谐振频率之间存在0.05 GHz左右的偏差,传感标签的灵敏度约为15 MHz·L/mg,最大阅读距离为24 cm,相比于商用氨气传感器,该传感标签在使用寿命、响应时间方面有明显优势。研究结果为畜禽场景的氨气无源检测提供了有效的理论和实践依据。展开更多
针对现有农田环境无线传感器网络在长期性、环保性和追踪性方面的不足,提出了一种基于无源射频识别(Radio frequency identification,RFID)传感标签的农田土壤环境监测技术。该RFID传感器标签基于超高频RFID通信协议,且工作于无源模式...针对现有农田环境无线传感器网络在长期性、环保性和追踪性方面的不足,提出了一种基于无源射频识别(Radio frequency identification,RFID)传感标签的农田土壤环境监测技术。该RFID传感器标签基于超高频RFID通信协议,且工作于无源模式下。提出了一种新的数据融合方式,比传统数据融合方式显著降低了系统工作的功耗以及响应时间。测试了电磁波在农田土壤中传输的损耗情况,确定了标签可正常工作的基本条件。针对埋入深度超过30 cm时传感器标签传输精确度不足的情况,提出在同一测量点布置两个传感器标签,通过天线极化方向的不同以获取更高的数据传输精确度。通过实验对所设计的温湿度传感器标签进行了通信性能及温湿度测量性能测试。实验结果表明,基于该无源RFID传感器标签所测试的温湿度与传统方式的测试结果基本一致,温度测试误差不超过1.5%,湿度测试误差不超过1%。与现有农田土壤环境监测方法相比,具有便利性强、成本低、寿命长、传感数据易于跟踪定位等显著优点。展开更多
为了增加射频识别(RFID)传感器的识读范围,针对无源超高频UHF(Ultra High Frequency)RFID标签的传感器接口,提出了一种新的低功耗低压时间数字转换器设计。该传感器接口采用基于游标原理的高效时数转换器,在保证分辨率和转换效率的同时...为了增加射频识别(RFID)传感器的识读范围,针对无源超高频UHF(Ultra High Frequency)RFID标签的传感器接口,提出了一种新的低功耗低压时间数字转换器设计。该传感器接口采用基于游标原理的高效时数转换器,在保证分辨率和转换效率的同时,能够实现较低的功耗和较大的动态范围。采用TSMC 90 nm标准CMOS技术设计并制造。测量结果显示相比其他类似结构,提出接口在输入时间范围28.18μs^42.94μs时有效分辨率为10.48 bits。采样率为20 ksample/s时,转换器转化效率为0.396 p J/bit,且功耗和电压供应分别仅为3.84μW和0.6 V,能够有效增强无源UHF RFID压力传感器标签的识读范围。展开更多
A wireless passive sensor array based on inductive-capacitive (LC) resonant circuits capable of simultaneously tracking two points of force loading is described. The sensor consisted of a planar spiral inductor connec...A wireless passive sensor array based on inductive-capacitive (LC) resonant circuits capable of simultaneously tracking two points of force loading is described. The sensor consisted of a planar spiral inductor connected to two capacitors forming a resonant circuit with two resonant frequencies. When a load was applied to one or both of the parallel plate capacitors, the distance between the plates of the capacitor was altered, thus shifting the observed resonant peaks. Testing illustrated that applied loading to a particular capacitor caused a significant shift in one of the resonant peaks and also a smaller shift in another resonant peak. This interdependence resulted from each capacitive element being connected to the same inductive spiral and was accounted for with a developed analysis algorithm. To validate the experimental observation, a circuit simulation was also generated to model the sensor behavior with changing force/displacement. The novelty of this system lies not only in its wireless passive nature, but also in the fact that a single LC sensor was fashioned to detect more than one point simultaneously.展开更多
This paper presents a passive EPC Gen-2 UHF RFID tag chip with a dual-resolution temperature sensor. The chip tag integrates a temperature sensor, an RF/analog front-end circuit, an NVM memory and a digital base- band...This paper presents a passive EPC Gen-2 UHF RFID tag chip with a dual-resolution temperature sensor. The chip tag integrates a temperature sensor, an RF/analog front-end circuit, an NVM memory and a digital base- band in a standard CMOS process. The sensor with a low power sigma-delta （NA） ADC is designed to operate in low and high resolution modes. It can not only achieve the target accuracy but also reduce the power consumption and the sensing time. A CMOS-only RF rectifier and a single-poly non-volatile memory （NVM） are designed to realize a low cost tag chip. The 192-bit-NVM tag chip with an area of 1 mm2 is implemented in a 0.18-#m standard CMOS process. The sensitivity of the tag is -10.7 dBm/-8.4 dBm when the sensor is disabled/enabled. It achieves a maximum reading/sensing distance of 4 m/3.1 m at 2 W EIRR The inaccuracy of the sensor is -0.6 ℃/0.5 ℃ （-1.0 ℃/1.2 ℃） in the operating range from 5 to 15 ℃ in high resolution mode （-30 to 50 ℃ in low resolution mode）. The resolution of the sensor achieves 0.02 ℃ （0.18 ℃） in high （low） resolution mode.展开更多
文摘氨气是畜禽场景中的主要有害气体之一,针对有源传感器不适于电路有线连接受限的畜禽场景问题,该研究基于高频电磁仿真软件(high frequency structure simulator,HFSS)设计了无源传感器仿真模型,选择聚酰亚胺(polyimide,PI)作为基板材料,采用丝网印刷技术研制了基于射频识别(radio frequency identification,RFID)原理的无源氨气传感标签。通过对氨气无源检测原理的解析,选择了具有高表面积的碳纳米管作为氨气敏感材料,推导了通过测量射频接收功率变化实现无源检测的数学模型;考虑谐振频率的动态调整,无源RFID传感标签采用开口间隙可调的裂环谐振器结构,通过分析传输系数的变化对RFID传感标签的检测过程进行模拟;搭建了用于实验室和畜禽场景氨气检测的射频测试系统,围绕功率反射系数、谐振频率、传输系数开展测试分析。试验结果表明,该标签检测效率易受到到二氧化碳、温湿度因素的影响,由于人工切割、基板变形、环境干扰等因素,实物标签的谐振频率与2.4 GHz的仿真谐振频率之间存在0.05 GHz左右的偏差,传感标签的灵敏度约为15 MHz·L/mg,最大阅读距离为24 cm,相比于商用氨气传感器,该传感标签在使用寿命、响应时间方面有明显优势。研究结果为畜禽场景的氨气无源检测提供了有效的理论和实践依据。
文摘针对现有农田环境无线传感器网络在长期性、环保性和追踪性方面的不足,提出了一种基于无源射频识别(Radio frequency identification,RFID)传感标签的农田土壤环境监测技术。该RFID传感器标签基于超高频RFID通信协议,且工作于无源模式下。提出了一种新的数据融合方式,比传统数据融合方式显著降低了系统工作的功耗以及响应时间。测试了电磁波在农田土壤中传输的损耗情况,确定了标签可正常工作的基本条件。针对埋入深度超过30 cm时传感器标签传输精确度不足的情况,提出在同一测量点布置两个传感器标签,通过天线极化方向的不同以获取更高的数据传输精确度。通过实验对所设计的温湿度传感器标签进行了通信性能及温湿度测量性能测试。实验结果表明,基于该无源RFID传感器标签所测试的温湿度与传统方式的测试结果基本一致,温度测试误差不超过1.5%,湿度测试误差不超过1%。与现有农田土壤环境监测方法相比,具有便利性强、成本低、寿命长、传感数据易于跟踪定位等显著优点。
文摘A wireless passive sensor array based on inductive-capacitive (LC) resonant circuits capable of simultaneously tracking two points of force loading is described. The sensor consisted of a planar spiral inductor connected to two capacitors forming a resonant circuit with two resonant frequencies. When a load was applied to one or both of the parallel plate capacitors, the distance between the plates of the capacitor was altered, thus shifting the observed resonant peaks. Testing illustrated that applied loading to a particular capacitor caused a significant shift in one of the resonant peaks and also a smaller shift in another resonant peak. This interdependence resulted from each capacitive element being connected to the same inductive spiral and was accounted for with a developed analysis algorithm. To validate the experimental observation, a circuit simulation was also generated to model the sensor behavior with changing force/displacement. The novelty of this system lies not only in its wireless passive nature, but also in the fact that a single LC sensor was fashioned to detect more than one point simultaneously.
基金supported by the National High-Tech Research and Development Program of China(No.2008AA010703)the National Natural Science Foundation of China(No.60976023)
文摘This paper presents a passive EPC Gen-2 UHF RFID tag chip with a dual-resolution temperature sensor. The chip tag integrates a temperature sensor, an RF/analog front-end circuit, an NVM memory and a digital base- band in a standard CMOS process. The sensor with a low power sigma-delta （NA） ADC is designed to operate in low and high resolution modes. It can not only achieve the target accuracy but also reduce the power consumption and the sensing time. A CMOS-only RF rectifier and a single-poly non-volatile memory （NVM） are designed to realize a low cost tag chip. The 192-bit-NVM tag chip with an area of 1 mm2 is implemented in a 0.18-#m standard CMOS process. The sensitivity of the tag is -10.7 dBm/-8.4 dBm when the sensor is disabled/enabled. It achieves a maximum reading/sensing distance of 4 m/3.1 m at 2 W EIRR The inaccuracy of the sensor is -0.6 ℃/0.5 ℃ （-1.0 ℃/1.2 ℃） in the operating range from 5 to 15 ℃ in high resolution mode （-30 to 50 ℃ in low resolution mode）. The resolution of the sensor achieves 0.02 ℃ （0.18 ℃） in high （low） resolution mode.
