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Radio Frequency (RF) analog circuit failures often occur in broadband, high voltage and high temperature environment, so how to determine fault location and forecast the time which failure is going to occur is an important topic. Based on actual working data of RF Low Noise Amplifier (LNA), a kind of RF circuit fault diagnosis method is put forward with the combination of K-means Clustering, Support Vector Machine (SVM) and Hidden Markov Model (HMM).Simulation results show that the combined method has (3 ~ 4)% recognition accuracy higher than that of the single algorithm. The proposed prognosis method is highly efficient in RF analog circuit fault diagnosis.

With the evolution of power electronic system to miniaturization and integration, dielectric capacitors are extensively studied in electric power systems such as electron beam and direction energy weapons owing to outstanding energy storage density and low loss. In this work, Pb0.97La0.02ZrO3 (PLZ) films were deposited on LaNiO3 (LNO)/Pt and LNO electrodes using sol-gel method, respectively. High spontaneous polarization (Ps ~ 91.3 μC cm−2) and low remanent polarization (Pr ~ 7.3 μC cm−2) can be obtained from PLZ/LNO/Pt/TiO2/SiO2/Si with energy storage density up to 25.4 J cm−3, which could be explained by good ohmic contact between films and composite electrodes. Besides, recoverable energy storage of films exhibits outstanding temperature stability (25.9–25.3 J cm−3) over -60 - 20 °C. These results suggest that LNO/Pt composite electrodes can be used to optimize PLZ films properties, which could be considered as a valid way for developing wide temperature range energy-storage capacitors.

Utilizing the single-photon detector, a direct-detection single-end Brillouin optical-fiber sensor is proposed and experimentally demonstrated for distributed temperature information measurement, which is an excellent candidate for the demodulation of frequency shift from Brillouin gain spectrum in conventional Brillouin schemes with coherent detection and frequency sweep. In our scheme, the ratio of the backscattered Rayleigh component and the Brillouin anti- Stokes signal is used to evaluate the ambient temperature along the fiber under test. Proof-of-concept experiments demonstrate 20dB dynamic range over 34km sensing fiber with a 0.96°C temperature error. In view of the good characteristics we achieved now, the photon-counting distributed Brillouin temperature sensor may be used in practical engineering fields such as smart grid.

The soft magnetic films (SMFs) using in monolithic microwave integrated circuits (MMICs) are suffered from the lower ferromagnetic resonance frequency f FMR and resistivity. In this study, Fe0.5Co0.5-ZnO films with high resistivity were fabricated by a compositional gradient sputtering on (0 1 1) lead zinc niobate–lead titanate (PZN-PT) substrates. It is interesting to note that the resistivity of the ZnO-doped Fe0.5Co0.5 films is 10–30 times larger than that of pure Fe0.5Co0.5 films. An ultrahigh f FMR of 10.48 GHz were achieved at electric field of 8 kV/cm without bias magnetic field. The excellent microwave ferromagnetic performances in as-deposited films can be attributed to two reasons: (1) the large uniaxial anisotropy field induced by gradient composition of doping ZnO, (2) the strong magnetoelectric coupling between the ferromagnetic/ferrielectric interfaces under the condition of high resistivity in Fe0.5Co0.5-ZnO films.

A multiparameter Brillouin fiber-optic sensor for distributed strain and temperature information measuring based on spontaneous scattering in a common communication optical fiber (the G. 652. D commercial fiber) is presented and experimentally demonstrated. Benefiting from the difference of the temperature and strain sensitivity from different Brillouin peaks with different acoustic modes, our proposed sensing configuration can be used to distinguish ambient temperature and applied strain at the same time, which is an excellent candidate to address the problem of cross-sensitivity in the classical Brillouin system. In the experimental section, using a 21.8 km sensing length of communication optical fiber, a temperature accuracy of 1.13°C and a strain accuracy of 21.46 με are obtained simultaneously. Considering the performance we achieved now, the proposed innovation and experimental setup will have some potential applications in the field of fiber sensors.

In large-signal simulations, building accurate models of power devices is essential for microwave circuit design. The traditional non-linear vector network measurement system is very complicated, and has the disadvantages of long test cycles and many measurement data. However, the powerful learning ability and accurate prediction ability of the extreme learning machine (ELM) neural network algorithm can be used to make up for the shortage of traditional measurement systems and improve the design efficiency. In this paper, an X-parameter model based on ELM neural network is established, the comparison of the model simulation with the actual circuit simulation shows that the fundamental error is within ±0.1 dBm and the second harmonic error is within ±0.3 dBm, which further verifies the correctness of the prediction model based on X-parameters of the ELM neural network.

This article proposes a novel temperature and humidity synchronization test method based on the U-shaped microwave resonator technology. U-shaped microwave resonator have been manufactured using the U-shaped microwave probe by studying the high quality factor, which was deponed on the length, distance of gap and radius of tungsten filament. Based on this U-shape microwave probe, the resonance frequency shift was using to detect the temperature and relative humidity with the sensitivity of 38 kHz/°C and 10.3 kHz/%RH, respectively. Meanwhile, the humidity can be detected by the resonance intensity with the signal noise ratio (SNR) of 100. Based on it, the temperature and relative humidity can be synchronization detected using the U-shaped microwave resonator. It proves a high sensitive, low-cost, ease of fabrication technologies.

A flexible mechanical deformation test system, which is a combination of the microwave and the flexible film, is proposed. The system consists of a U-shaped microwave resonator, coaxial transmission line, and PDMS flexible substrate. Microwave signals are generated from the vector network analyzer and loaded to the coaxial transmission line and then coupled to the U-shaped resonator through the coupling loop. The resonator works at the gigahertz band with the test range from 3 GHz to 40 GHz. The resonant frequency of the resonator can be adjusted by changing the shape of PDMS, and the related signals can be detected by using the S11 parameter of the microwave. The response time of the U-shaped resonator is less than 20 ms, and the sensitivity on the curved surface is 12.5 Hz/nm.

In conventional phase noise metrology, the phase noise of an oscillator is measured by instruments equipped with specialized and sophisticated devices. Such hardware-based testing usually requires high-performance and costly apparatuses. In this paper, we carried out a novel phase noise measurement method based on a mathematical model. The relationship between the phase noise of a radio frequency oscillator and its power spectral density (PSD) was established, different components of the power law phase noise were analyzed in the frequency domain with their characteristic parameters. Based on the complete physical model of an oscillator, we fitted and extracted the parameters for the near-carrier Gaussian and the power law PSD with Levenberg-Marquardt optimization algorithm. The fitted parameters were used to restore the power law phase noise with considerable precision. Experimental validation showed an excellent agreement between the estimation from the proposed method and the data measured by a high-performance commercial instrument. This methodology can be potentially used to realize fast and simple phase noise measurement and reduce the overall cost of hardware.

A Back-Propagation Neural Network (BPNN) nonlinear model of $GaN$ HEMT is proposed, which can adaptively fit the nonlinear parameter relationship, and reduce computation. The network weights are obtained automatically, and then the nonlinear mapping relation is determined. The comparison between BPNN model and test data proves the good consistency.

A nondestructive detection method for drugs in the medicine box base on three dimensional terahertz imaging is proposed in this paper. It is able to complete nondestructive detection without opening the medical box by using the characteristics of high resolution, penetrating and security. An active 3-D THz imaging system consists of a vector network analyzer, a THz spread spectrum device, THz antennas, and a mechanical scanning system is used. The operating frequency of the imaging system is from 220GHz to 325GHz. A modified range migration algorithm is adopted after a phase calibration. As a result, drugs in the medicine box with missing one are detected via the 3-D THz imaging system with a high resolution. The 3-D imaging result is consistent with the reality which proves that the detecting method base on 3-D THz imaging for drugs in the medical box is effective.

Ahstract-A novel TRM calibration procedure aimed to improve the quality of on-wafer S-parameter measurement, especially in mm-wave frequency band, has been proposed. This procedure is based on active reverse signal injections to improve the accuracy of the raw thru s-parameter measurement. This calibration method can effectively improve the S-parameter measurement quality at mm-wave frequency and hence improve the modelling accuracy. This new optimized calibration method eliminates the need of utilizing complex and expensive loadpull system or post calibration optimization algorithms, and can be easily implemented in modelling extraction process or further implemented into other LRL/TRL based calibration algorithms. Finally, this proposed method has been tested on a real measurement system over a 16nm FinFET CMOS device to test its validity.

Pulse modulation is of great importance in radar system. The performance of pulse modulated oscillating signal is usually characterized by its phase noise. The phase noise of pulse modulated signal can be hardly measured by phase demodulation. The correlation between the carrier and modulated signal needs to be established for the purpose of noise characterization. In this work, a mathematical form of phase noise of pulse modulated signal was proposed in the frequency domain. After pulse modulation, phase noise distribution of the oscillator shifts and superimposes upon the harmonics of the modulating pulse. Experiments were carried out to verify the phase noise property. The obtained results show that by referring to the phase noise of carrier, the phase noise measured by instrument is in good agreement with the mathematical prediction. The phase noise of pulse width modulated signal can be well depicted by the proposed mathematical form.

Since the application of high power microwave weaons and the complication of electronic systems, the problem of passive intermodulation becomes more important. In this paper, we discussed the causes, impact, and measurement of PIM according to the present status in the passive intermodulation distortion test. Build testing system based on the concept of sharing platform, in engineering practice, the test system can test the PIM characteristics of microwave components offor a specific application needs flexibly. This paper analyzed the error and studied the unstable factors of the test system, then this paper put forward the matters needing attention to improve the accuracy of PIM systems.

This paper describes an improved method for calculating permittivity and permeability based on time-domain measurement function of VNA without resonant effect in broadband frequency range, and analyzes multi-reflection effect between two ports of sample. The measurement method for broadband material's property uses a two-port transmission line for fixture, and the permittivity mu(omega) and permeability epsiv(omega) are calculated by the characterized impedance z(omega) and propagation constant y(omega) of the region loaded materials. The computer simulation and experiment results adopting the time-domain method are satisfying.