A Vector Network Analyzer(VNA)can be used to identify oscillation frequency of a signal source with moderate or low Radio Frequency(RF)power if certain care is taken according to experimental results.Unlike reported i...A Vector Network Analyzer(VNA)can be used to identify oscillation frequency of a signal source with moderate or low Radio Frequency(RF)power if certain care is taken according to experimental results.Unlike reported in the literature that a resonant peak of measured absolute value of reflection coefficient greater than 1 that corresponds to an oscillation frequency,we report that by observing the magnitude change of one-port reflection coefficient across the entire swept frequency range,a sudden peak or a dip corresponds to an oscillation frequency,this is more accurate than other reports.In addition,using modern VNA as a signal detection method can significantly reduce measurement time and increase measurement accuracy to VNA capability for developing emerging signal generating devices at early stage,especially for planar,large quantity and operating in a wide frequency range.展开更多
As a simple,fast,and non-destructive measuring technology,dielectric spectroscopy is usually used to analyze the dielectric properties of agricultural products and food,and then to predict the main components of mater...As a simple,fast,and non-destructive measuring technology,dielectric spectroscopy is usually used to analyze the dielectric properties of agricultural products and food,and then to predict the main components of materials.However,the large and expensive vector network analyzers(VNA)with expensive analysis software applied in measuring dielectric properties make research limited to the laboratory.To acquire dielectric spectra in situ,a model for solving relative complex permittivity was derived,and its performance was validated.Then,a low-cost portable dielectric spectrometer with a mini VNA,a Raspberry Pi,and a coaxial probe as core parts was developed over the frequency range of 100-3000 MHz.The stability and accuracy of the developed spectrometer were tested using milk and juice.The results indicated that the relative errors of the model were within±5%for dielectric constant(ε′)and loss factor(ε″).The coefficients of variation of measuredε′andε″by the developed spectrometer at 100-3000 MHz were less than 1%and 2%,respectively.Compared with the dielectric properties obtained by using a commercial dielectric measurement system,the relative errors of measuredε′andε″were within±3.4%and±6.0%,respectively.This study makes fast,non-destructive,and on-site food quality detection using dielectric spectra possible.展开更多
We develop a high resolution ground penetrating radar system （LANRCS-GPR） based on the E5071B Vector Network Analyzer （VNA）. This system takes advantage of a wideband and adjustable frequency domain ground penetra...We develop a high resolution ground penetrating radar system （LANRCS-GPR） based on the E5071B Vector Network Analyzer （VNA）. This system takes advantage of a wideband and adjustable frequency domain ground penetrating radar system and adds the characteristics of a network analyzer with ultra-wideband and high precision measurement. It adopts the LAN mode to concatenate system control that reduces construction cost and makes the system easy to expand. The high resolution ground penetrating radar system carries out real time imaging using F-K migration with high calculation efficiency. The experiment results of the system indicate that the LANRCS-GPR system provides high resolution and precision, high signal-to-noise ratio, and great dynamic range. Furthermore, the LANRCS-GPR system is flexible and reliable to operate with easy to expand system functions. The research and development of the LANRCS-GPR provide the theoretical and experimental foundation for future frequency domain ground penetrating radar production and also can serve as an experimental platform with high data gathering precision, enormous information capability, wide application, and convenient operation for electromagnetic wave research and electromagnetic exploration.展开更多
文摘A Vector Network Analyzer(VNA)can be used to identify oscillation frequency of a signal source with moderate or low Radio Frequency(RF)power if certain care is taken according to experimental results.Unlike reported in the literature that a resonant peak of measured absolute value of reflection coefficient greater than 1 that corresponds to an oscillation frequency,we report that by observing the magnitude change of one-port reflection coefficient across the entire swept frequency range,a sudden peak or a dip corresponds to an oscillation frequency,this is more accurate than other reports.In addition,using modern VNA as a signal detection method can significantly reduce measurement time and increase measurement accuracy to VNA capability for developing emerging signal generating devices at early stage,especially for planar,large quantity and operating in a wide frequency range.
基金financial support provided by the National Natural Science Foundation of China(Grant No.32172308)Startup Foundation for Doctors of Yan'an University(No.YDBK2022-79).
文摘As a simple,fast,and non-destructive measuring technology,dielectric spectroscopy is usually used to analyze the dielectric properties of agricultural products and food,and then to predict the main components of materials.However,the large and expensive vector network analyzers(VNA)with expensive analysis software applied in measuring dielectric properties make research limited to the laboratory.To acquire dielectric spectra in situ,a model for solving relative complex permittivity was derived,and its performance was validated.Then,a low-cost portable dielectric spectrometer with a mini VNA,a Raspberry Pi,and a coaxial probe as core parts was developed over the frequency range of 100-3000 MHz.The stability and accuracy of the developed spectrometer were tested using milk and juice.The results indicated that the relative errors of the model were within±5%for dielectric constant(ε′)and loss factor(ε″).The coefficients of variation of measuredε′andε″by the developed spectrometer at 100-3000 MHz were less than 1%and 2%,respectively.Compared with the dielectric properties obtained by using a commercial dielectric measurement system,the relative errors of measuredε′andε″were within±3.4%and±6.0%,respectively.This study makes fast,non-destructive,and on-site food quality detection using dielectric spectra possible.
文摘在三通道二端口矢量网络分析仪(Vector Network Analyzer,VNA)的校准过程中,引入长度未知的50欧姆传输线段作为校准件代替常见的短路-开路-匹配-直通(Short-Open-Load-Thru,SOLT)校准算法中的匹配校准件,减少了校准件数量且不需要已知校准件的全部特性,不仅降低了测试成本,同时简化了测试步骤.通过这种校准算法不必计算各个系统误差项的大小,待测件(Device Under Test,DUT)的散射矩阵直接由校准和测试过程中的散射参数测量值表示得到.最后,利用此方法计算二端口待测件的真实散射参数,并与SOLT算法进行对比,其结果吻合良好.
基金This project was supported by National Natural Science Foundation of china (No.40474042)
文摘We develop a high resolution ground penetrating radar system （LANRCS-GPR） based on the E5071B Vector Network Analyzer （VNA）. This system takes advantage of a wideband and adjustable frequency domain ground penetrating radar system and adds the characteristics of a network analyzer with ultra-wideband and high precision measurement. It adopts the LAN mode to concatenate system control that reduces construction cost and makes the system easy to expand. The high resolution ground penetrating radar system carries out real time imaging using F-K migration with high calculation efficiency. The experiment results of the system indicate that the LANRCS-GPR system provides high resolution and precision, high signal-to-noise ratio, and great dynamic range. Furthermore, the LANRCS-GPR system is flexible and reliable to operate with easy to expand system functions. The research and development of the LANRCS-GPR provide the theoretical and experimental foundation for future frequency domain ground penetrating radar production and also can serve as an experimental platform with high data gathering precision, enormous information capability, wide application, and convenient operation for electromagnetic wave research and electromagnetic exploration.
