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In this paper, behavioral modeling of a driver amplifier is implemented by using S2P and S2D model setup. By using the standard silicon-based driver amplifier for obtaining the measured results of Scattering (S)- parameters and large signal parameters for temperatures 25°C and 85°C. These parameters are imported into the S2P and S2D models to perform the small signal and large signal analysis at 3 GHz frequency for temperatures 25°C and 85°C. Then, the simulated results are compared with the measured results to verify the efficient utilization of behavioral models. The novelty of this work deals with the simulation study of the characteristics of a silicon-based driver amplifier, which are obtained directly from the measurements. This proposed method is essential for performing hetero-integration of transceiver design, which can be further utilized to improve the efficiency of transceiver for high-frequency band. At last, the study of relative error performance analysis between measured and simulated results of different parameters is carried out and calculated value of NMSE (in %) for S11, S12, S21, S22, gain, pout, 1 dB compression point, ACP, 3rd harmonics, 4th harmonics, and 5th harmonics are 0.0083, 0.0055, 0.0086, 0.011, 0.0844, 0.814, 0.926, 0.71, 0.22, 0.012 and 0.070 respectively. [ABSTRACT FROM AUTHOR]

This article introduces an innovative methodology for measuring the impedance of RFID (Radio Frequency Identification) chips. The primary objective is to develop a technique that enables impedance measurement across a range of frequencies, centered around the critical operational frequency of RFID systems, specifically 13.56 MHz. Unlike conventional methods, which typically focus solely on the impedance at 13.56 MHz, this approach utilizes the reflection coefficient of the device under test (DUT) to measure impedance over a broader frequency spectrum. This spectrum encompasses the frequencies within the ISO14443 communication bandwidth. The excitation signal is carefully selected to closely mimic an actual RFID communication frame. The experimental results demonstrate the feasibility of this method by comparing the impedance measurements of passive component pairs against those obtained using a vector network analyzer (VNA). Subsequently, the technique is applied to an RFID chip, underscoring its practical applicability and accuracy. [ABSTRACT FROM AUTHOR]

This study presents a new approach for characterizing the 3D printing electromagnetic properties in Polylactic Acid (PLA) using a novel cross-fractal sensor. The CST Studio Suite simulation, employing the finite element method (FEM), and the ADS simulation software, based on the equivalent circuit of this novel sensor, are utilized to enhance confidence in the convergence of simulation and measurement results. The analysis confirms that the real sensor, based on a cross-sectional fractal resonator, exhibits excellent sensitivity, selectivity, and linearity. Sensor performance is evaluated through two methods: the frequency-based approach and the S11 parameter analysis. In the frequency-based method, the sensor demonstrates a typical sensitivity of 0.0302 GHz/cm3, while in the S11 parameter analysis, it exhibits a typical sensitivity of 0.3065 dB/cm3. These results underscore the high sensitivity and linearity of this innovative sensor. The using of this novel cross fractal sensor, it promises to show how to properly adjust 3D printer parameters, potentially setting the “infill percentage” of the 3D print, this is because the proportion of air present changes when the printing percentage is changed, which can lead to ( $\varepsilon \text{r}$ ) and loss-tangent (tan ( $\delta$ )) with varying the infill percentage, by the resonance frequency (fr) approach demonstrates a characteristic sensitivity of 0.1822 GHz/RIU. The experimental study confirmed that the fabricated sensor exhibits miniaturization (with an electrical size of $\lambda 0$ /8), high sensitivity, and excellent linearity in the frequency approach, with a typical sensitivity of 0.004615 GHz/%. The suggested biosensor demonstrated its capability to detect low concentrations of ethanol. These aqueous solutions, containing known alcohols like ethanol in low concentrations, enables identification of Halal and alcohol-free products in food sensing applications.

The early detection and diagnosis of cancer presents significant challenges in today's healthcare. So, this research, suggests an original experimental biosensor for cell cancer detection using a corona-shaped metamaterial resonator. This resonator is designed to detect cancer markers with high sensitivity, selectivity, and linearity properties. By exploiting the unique properties of the corona metamaterial structure in the GHz regime, the resonator provides enhanced interaction of electromagnetic waves and improved detection skills. Through careful experimental, simulation, and optimization studies, we accurately demonstrate the resonator's ability to detect cancer. The proposed detection system is capable of real-time non-invasive cancer detection, allowing for rapid intervention and better patient outcomes. The sensitivity value was confirmed through simulation, estimated at 0.1825 GHz/RIU. The results of two different simulation methods are used: the simulation software CST Studio Suite (version 2017) based on the finite element method (FEM), and the simulation software ADS (version 2019) based on the equivalent circuit method, thereby increasing confidence in the convergence of simulation and measurement results. This work opens new avenues for developing advanced detection technologies in the field of oncology, and paves the way for more effective cancer diagnosis. The experimental study verified that this realized sensor has very small frequency shifts, significantly small electrical dimension and miniaturization, high sensitivity, and good linearity. The suggested configurations showed a capacity for sensing cancer cells in the GHz regime. [ABSTRACT FROM AUTHOR]

In this study, GdMnO3-Ba(Zn1/3Nb2/3)O3 was manufactured using the mixture of oxides technique. GdMnO3-Ba(Zn1/3Nb2/3)O3 compositional compounds were formed in various ratios for structural analysis. Single-phase composition of GdMnO3 and Ba(Zn1/3Nb2/3)O3 were produced after sintering between 1200-1400°C. Structural analysis results showed that the second phase did not occur in GdMnO3 and Ba(Zn1/3Nb2/3)O3. X-ray diffraction (XRD) was performed for structural analysis. In addition, GdMnO3/PANI/Ba(Zn1/3Nb2/3)O3 composites were produced by hot pressing method using various amounts of GdMnO3-Ba(Zn1/3Nb2/3)O3 and aniline. The weight ratios of (GdMnO3- Ba(Zn1/3Nb2/3)O3) and aniline were 1:1, respectively. The GdMnO3/PANI/Ba(Zn1/3Nb2/3)O3 compound formed in various weights, and epoxy powder were used to produce microwave shielding effect composites. Using a network analyzer (NA), the microwave shielding effect of GdMnO3/PANI/Ba(Zn1/3Nb2/3)O3 composites was investigated in the range of 8-18 GHz. A minimum shielding effect value of -56.77 dB was obtained at 15.77 GHz at 1.4 mm thickness. The GdMnO3/PANI/Ba(Zn1/3Nb2/3)O3 was produced as composite material and their properties were characterized for shielding effect. This microwave shielding performance can be easily adjusted by controlling the polyaniline content and GdMnO3-Ba(Zn1/3Nb2/3)O3 content in the samples for wider and required frequency bands. [ABSTRACT FROM AUTHOR]

Stainless steel with a galvanic copper coating is often used as a material for the radio-frequency (RF) cavities of linear ion accelerators. However, for cavities with complex inner surfaces obtaining a uniform copper coating is technologically challenging. The solution might be found in manufacturing a cavity without a copper coating, though in this case the amount of power losses in the cavity should be carefully estimated. To get such an estimation, an experiment is carried out where the electrodynamic properties of a test cavity with two coupling loops are measured with stainless-steel samples placed inside it. The results of this experiment show a sufficient difference between the simulated and measured Q factor values for the same 12Cr18N10Т sample steel grade. Thus, an assumption is made that the magnetic properties of austenitic steel samples could have changed during the manufacturing process. The magnetic-permeability values for the steel samples are also estimated. [ABSTRACT FROM AUTHOR]

Problems in measuring electromagnetic parameters for the sensors of different physical quantities, such as temperature, humidity, and radiation intensity, are well known. In some cases, for example, when measuring cryogenic temperatures, it is fundamentally important to minimize the number of cables connecting a sensor to the measuring device. In this paper, a method is developed for determining the electromagnetic parameters of a group of four sensors using only four communication cables between a sensor and a measuring device. For different configurations connecting the sensors to a group, the interrelations between the resistances of each sensor with the measured quadripole A-parameters, as well as the identities connecting between the elements of the A-parameter matrices of the sensor group with each other in the cases of different methods for connecting to a measuring device have been obtained. The proposed method makes it possible to provide an increase in the determination accuracy for sought-for electromagnetic parameters via performing multiple independent measurements. [ABSTRACT FROM AUTHOR]

In an effort to reduce switching loss, increase switching frequencies, and shrink passive component sizes, power device switching times are being pushed into nanosecond and subnanosecond intervals. However, these fast switching times require high rates of change of current making the power devices susceptible to overvoltage damage from parasitic inductance in the power loop. This presents challenges in measuring the device switching current accurately and, in turn, makes accurate measurements of device switching energy and stored charge difficult. Traditional current measurement methods either do not have the required frequency response to view the switching edge accurately or have a high parasitic inductance that can significantly alter switching performance and cause damage to the power device. In this article, an active current measurement system is developed. This circuit achieves up to 1.6-GHz bandwidth with zero overshoot. By utilizing mutual inductance cancellation, an insertion inductance down to 20 pH has been achieved. The research performed in this article thereby allows for an accurate measurement of device switching loss with minimal power circuit disturbance. The performance of this current measurement is experimentally verified in the frequency domain using a vector network analyzer, and time-domain switching measurements are compared with state-of-the-art current measurement. [ABSTRACT FROM AUTHOR]

The early detection and diagnosis of cancer presents significant challenges in today’s healthcare. So, this research, suggests an original experimental biosensor for cell cancer detection using a corona-shaped metamaterial resonator. This resonator is designed to detect cancer markers with high sensitivity, selectivity, and linearity properties. By exploiting the unique properties of the corona metamaterial structure in the GHz regime, the resonator provides enhanced interaction of electromagnetic waves and improved detection skills. Through careful experimental, simulation, and optimization studies, we accurately demonstrate the resonator’s ability to detect cancer. The proposed detection system is capable of real-time non-invasive cancer detection, allowing for rapid intervention and better patient outcomes. The sensitivity value was confirmed through simulation, estimated at 0.1825 GHz/RIU. The results of two different simulation methods are used: the simulation software CST Studio Suite (version 2017) based on the finite element method (FEM), and the simulation software ADS (version 2019) based on the equivalent circuit method, thereby increasing confidence in the convergence of simulation and measurement results. This work opens new avenues for developing advanced detection technologies in the field of oncology, and paves the way for more effective cancer diagnosis. The experimental study verified that this realized sensor has very small frequency shifts, significantly small electrical dimension and miniaturization, high sensitivity, and good linearity. The suggested configurations showed a capacity for sensing cancer cells in the GHz regime.

Copyright of Journal of South China University of Technology (Natural Science Edition) is the property of South China University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A frequency spectrum segmentation methodology is proposed to extract the frequency response of circuits and systems with high resolution and low distortion over a wide frequency range. A high resolution is achieved by implementing a modified Dirichlet function (MDF) configured for multi-tone excitation signals. Low distortion is attained by limiting or avoiding spectral leakage and interference into the frequency spectrum of interest. The use of a window function allowed for further reduction in distortion by suppressing system-induced oscillations that can cause severe interference while acquiring signals. This proposed segmentation methodology with the MDF generates an interleaved frequency spectrum segment that can be used to measure the frequency response of the system and can be represented in a Bode and Nyquist plot. The ability to simulate and measure the frequency response of the circuit and system without expensive network analyzers provides good stability coverage for reliable fault detection and failure avoidance. The proposed methodology is validated with both simulation and hardware. [ABSTRACT FROM AUTHOR]

A frequency spectrum segmentation methodology is proposed to extract the frequency response of circuits and systems with high resolution and low distortion over a wide frequency range. A high resolution is achieved by implementing a modified Dirichlet function (MDF) configured for multi-tone excitation signals. Low distortion is attained by limiting or avoiding spectral leakage and interference into the frequency spectrum of interest. The use of a window function allowed for further reduction in distortion by suppressing system-induced oscillations that can cause severe interference while acquiring signals. This proposed segmentation methodology with the MDF generates an interleaved frequency spectrum segment that can be used to measure the frequency response of the system and can be represented in a Bode and Nyquist plot. The ability to simulate and measure the frequency response of the circuit and system without expensive network analyzers provides good stability coverage for reliable fault detection and failure avoidance. The proposed methodology is validated with both simulation and hardware.

This research work assumes the role of designing a Micro-strip patch antenna that exists within the band range of 402 MHz to 405 MHz, which was considered as medical implantable communication systems (MICS) band and can be possibly implanted at human body phantom model because of its flexibility and lower radiation characteristics. CST microwave studio was used for designing the patch antenna and the human body phantom model with the existence of homogeneous layers (fat, skin and muscle) and the final version was fabricated. Being highly flexible, FR4 was chosen as a substrate to maintain 0.5 mm thickness throughout. For the ground and patch, copper material was selected having thickness of 0.018 mm. For the ease of fabrication and biocompatibility, silicon was selected with the thickness of being 8 mm. Maximum specific absorption rate of the proposed antenna was obtained 0.588 W/Kg for 10 g tissue. Various Parameters such as VSWR, S11, Radiation efficiency, Total efficiency were found 1.1889, -21.28 dB, -45.71 dB, -45.74 dB respectively inside body phantom that ensure the antenna design was efficiently and effectively suitable for biotelemetry system which is body implantable. After fabrication the value of S11 is found -12.43 dB in open space with 453 MHz frequency. [ABSTRACT FROM AUTHOR]

High bandwidth sensors are required to measure the wide-bandgap devices’ transient behavior because of their fast switching speed. In addition to high bandwidth, the current sensor must introduce little extra parasitic inductance to the switching power loop. The analysis of conventional shunt resistors shows the key to high bandwidth is the coaxial structure and its parasitic inductance is proportional to its transient heat energy rating. By combining the structure of coaxial shunt resistor and alumina substrate surface mount thin film resistors, a novel surface mount coaxial shunt resistor is introduced. Experimental measurement verifies its capability of achieving very high bandwidth while introducing very low parasitic inductance. The design can achieve up to 2.23-GHz measurement bandwidth while keeping its parasitic inductance as low as 0.12 nH. Application in gallium nitride heterojunction-field-effect-transistors double pulse test shows it can faithfully capture the transient current waveform while introducing little interference to the switching behavior. [ABSTRACT FROM AUTHOR]

In this paper, compact linear dual polarized series-fed 1 × 2 linear and 2 × 2 planar arrays antennas for airborne SAR applications are proposed. The proposed antenna design consists of a square radiating patch that is placed on top of the substrate, a quarter wave transformer and 50-Ω matched transformer. Matching between a radiating patch and the 50-Ω microstrip line is accomplished through a direct coupled-feed technique with the help of an impedance inverter (λ/4 impedance transformer) placed at both horizontal and vertical planes, in the case of the 2 × 2 planar array. The overall size for the prototype-1 and prototype-2 fabricated antennas are 1.9305 × 0.9652 × 0.05106 λ03 and 1.9305 × 1.9305 × 0.05106 λ03, respectively. The fabricated structure has been tested, and the experimental results are similar to the simulated ones. The CST MWS simulated and vector network analyzer measured reflection coefficient (S11) results were compared, and they indicate that the proposed antenna prototype-1 yields the impedance bandwidth > 140 MHz (9.56–9.72 GHz) defined by S11 < −10 dB with 1.43%, and S21 < −25 dB in the case of prototype-2 (9.58–9.74 GHz, S11 < −10 dB) > 140 MHz for all the individual ports. The surface currents and the E- and H-field distributions were studied for a better understanding of the polarization mechanism. The measured results of the proposed dual polarized antenna were in accordance with the simulated analysis and showed good performance of the S-parameters and radiation patterns (co-pol and cross-pol), gain, efficiency, front-to-back ratio, half-power beam width) at the resonant frequency. With these features and its compact size, the proposed antenna will be suitable for X-band airborne synthetic aperture radar applications.

The design and implementation of a multifrequency and multispectral diffuse optical tomography system is described. Four wavelengths are utilized: 665, 785, 808, and 830 nm. The system is based on a network analyzer, which provides rf modulation signals for the laser diodes, as well as measures the amplitude and the phase of the detected signals. Six different modulation frequencies ranging from 110 to 280 MHz are used. The details of instrumentation, calibration, data acquisition, and performance of the system are given. A finite element algorithm is used to solve the diffusion equation, and an inverse solver based on this forward solver is implemented to calculate the absorption and scattering maps from the acquired data. Data acquisition for one wavelength is completed in less than 2.5 min for a single modulation frequency. The measurement repeatability is 0.5% in ac intensity and 0.2 deg in phase. The performance of the system is evaluated with phantom studies. A multifrequency reconstruction algorithm is used, in which a single absorption and scattering image pair is obtained using the whole dataset obtained at different modulation frequencies. It is shown that the multifrequency reconstruction approach provides superior image quality compared to the single frequency counterpart. (c) 2006 Society of Photo- Optical Instrumentation Engineers.

Software-Defined Radio (SDR) has appeared as a sufficient framework for the development and testing of the measurement systems such as a signal generator, signal analyzer, and network analysis used in the network analyzer. However, most of researchers or scientists still rely on commercial analyzers were larger benchtop instruments, highly cost investment and minimum software intervention. In this paper, a new concepts measurement revolution called as Software Defined Instrumentation (SDI) on network analysis is presented, which is based on reconfigurable SDR, a low-cost implementation, ability to access RF chain and utilizing open source signal processing framework. As a result, a Vector Network Analyzer (VNA) has been successful implemented by deploying an SDR platform, test sets, and data acquisition from the GNU Radio software in host PC. The known calibration process on SHORT-OPEN-LOAD (SOL) technique is validated to ensure measurement data from this SDI free from systematic error. Two types of SOL calibration standards used for a comparison study to validate the SDI measurement system which is capable of generating the response on the differential of standard quality and accuracy of standards kits. Finally, calibration uncertainty analysis is also presented in this work by utilizing RF open source package without any cost addition. [ABSTRACT FROM AUTHOR]

Highlights • Microwave spectra of eggs were acquired using a waveguide and network analyzer. • Artificial neural network was able to predict the quality indices of shell eggs. • Soft independent modeling of class analogy classified the eggs based on storage time. Abstract A rectangular waveguide equipped with a network analyzer was used to assess the quality indices of shell egg. The scattering parameters of the eggs were acquired in the range of 0.9–1.7 GHz and they were then used to calculate microwave spectra of the samples. PLS and ANN regression methods were implemented to predict the egg quality indices and SIMCA and ANN classification methods were applied to classify the eggs based on their storage time. The best predictive models, however, obtained from ANN analysis where the yolk coefficient, air cell height, thick albumen height, Haugh unit, and albumen pH could be predicted with the residual predictive deviation (RPD) values of 3.500, 3.000, 2.411, 2.033, and 1.829, respectively. To classify the eggs according to their storage time, both SIMCA and ANN analyses resulted in the total accuracy of 100% when return loss spectra were used as the input. [ABSTRACT FROM AUTHOR]

• Effect of magnetic permeability is observed on permittivity measurement of ferrites. • EM modeling and impedance measurements are carried out to verify the same. • Smith chart analysis of permittivity measurement is done using reflection technique. • Slotted sample & fixture are discussed, for the accurate permittivity measurement. This paper presents the effect of magnetic permeability on the permittivity measurement using coaxial line reflection technique. It discusses in detail about the design aspects, analysis and simulation of the slotted co-axial sample and fixture for dielectric characterization of the ferrites and garnets possessing both dielectric and magnetic properties. This technique makes use of improved coaxial fixture and APC 07 compatible slotted coaxial sample geometry to measure the complex permittivity of the ferrite material. Permittivity is calculated from the impedance of sample loaded fixture, which is independent of magnetic permeability, because of air slot cut in the coaxial hollow cylindrical sample along the length. Characterization data of dielectrics and ferrites is used in design of ferrite circulators, and pulse magnets for particle accelerator applications. This is also used in many other RF applications including design of dielectric resonator for spin wave line width measurement of ferrites. Design work is aimed at accurate measurement of complex permittivity; using reflection measurement in coaxial fixture over a wide frequency range of 20 kHz to 1 GHz. Reflection measurement technique is further explored for accurate measurement of complex permittivity. [ABSTRACT FROM AUTHOR]

Oil palm fresh fruit bunch (OPFFB) is the main export product of the oil palm industry. A good oil palm is between 17 to 18 weeks of age with full fruitless maturity. An automated detection system should be implemented to determine the OPFFB's maturity and expedite the harvesting process. Various automated detection methods have been proposed for conventional method replacement. In a preliminary study, a new oil palm fruit sensor was proposed for detecting the maturity of OPFFB, and a microstrip ring resonator was designed for determining the moisture content in oil palm fruit. The coaxial feeder of the microstrip ring was a Sub-Miniature A (SMA) stub contact panel with outer and inner conductors of 4.1 mm and 1.3 mm, respectively. The measurement system consisted of a sensor and a PC controlled network analyzer. This system was tested successfully on seeds and fruits of oil palm with various degrees of maturity. The microstrip ring resonator operated between 2.2 and 3 GHz and required low frequency that enabled the electromagnetic field in the first half of the ring resonator to be transferred to the second half and subsequently cause the collinearity of the maximum field points in the feed lines and resonator. [ABSTRACT FROM AUTHOR]

Copyright of Experimental Technology & Management is the property of Experimental Technology & Management Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To calibrate the test system of fifth-generation (5G) massive multiple-input multiple-output (MIMO) base station (BS), this paper proposes a promising single-port measurement scheme, which is more cost-effective and convenient than conventional scheme. The conventional scheme first requires the disconnection of the measurement equipment from the BS test system, and then uses a costly vector network analyzer (VNA) for the system calibration measurement, which is cumbersome, slow, and inconvenient. Instead, the proposed scheme can conduct the system calibration with low cost directly based on the existing measurement equipment in the original test system, i.e. no need for the extra expensive VNA. The accuracy performance of the proposed scheme is evaluated by the frequency response error measured between the proposed and the conventional schemes, e.g. with an amplitude error range of [ − 0. 45 , 0.14] dB and a phase error range of [ − 0. 2 ∘ , 2. 5 ∘ ]. Therefore, the superiority is that the proposed single-port scheme in this paper accomplished the equivalent measurement as the conventional scheme, and further reduced the cost and inconvenience for the test industry. Finally, the reduced cost and complexity by the proposed measurement scheme is beneficial to both the industry and academic scientific world in terms of faster and more efficient testing as well as increased reproducibility of research findings. • Single-port scheme accomplishes the equivalent measurement as the reference scheme. • Calibration process is done with on need for the extra expensive network analyzer. • Comb generator units boost cost-effective and convenient calibration of test system. [ABSTRACT FROM AUTHOR]

We have developed a high-bandwidth frequency-domain photon migration (FDPM) instrument which capable of noninvasively determining the optical properties of biological tissues in near-real-time. This portable, inexpensive, diode-based instrument is unique in the sense that we employ direct diode laser modulation avalanche photodiode detection. Diffusion models were used to extract the optical properties (absorption and transport scattering coefficients) of tissue-simulating solution from the 300 kHz to 1 GHz photon density wave data.

We have developed a high-bandwidth frequency-domain photon migration (FDPM) instrument which capable of noninvasively determining the optical properties of biological tissues in near-real-time. This portable, inexpensive, diode-based instrument is unique in the sense that we employ direct diode laser modulation avalanche photodiode detection. Diffusion models were used to extract the optical properties (absorption and transport scattering coefficients) of tissue-simulating solution from the 300 kHz to 1 GHz photon density wave data.

A balance-unbalance (balun) transformer is commonly used to connect the balance 100 Ohm twisted pair cable to the unbalance 50 Ohm network analyzer ports, but due to the limitations of the core (i.e. ferrite) inside the balun, the balun can only effectively operates at a certain band of frequencies. This limitation can be eliminated by using a 4-port vector network analyzer (VNA) which is done by connecting the VNA’s ports to each conductor end. The extracted S-parameters will then be transformed to a 2-port S-parameters in differential mode at both ports. To validate the measurement technique, S-parameter measurement by using the 4-Port Network Analyzer without any balun will be compared to the measurement which used the 2-Port Network Analyzer with the balun transformers. Two twisted pair cable distances are selected as reference which are 500, and 1000 meters with nominal copper diameter of 0.5mm. Based on the measurement results, the 4-ports measurement shows good correlation with the 2-ports measurement especially at 500m distance. This shows that the 4-ports measurement setup is suitable to be used to measure twisted pair copper cable and possible to measure at a higher frequency band such as up to 500 MHz but at a shorter twisted pair cable distance. [ABSTRACT FROM AUTHOR]

The cavity resonator is one of the widely used components in the microwave applications. The unloaded Q, the resonant frequency, and the coupling factor are basic parameters of a cavity. A simple unloaded Q factor measurement procedure of a cavity is proposed in a lossy coupling. The equivalent circuit of a cavity with coupling loss at near the resonant frequency is presented. The coupling loss resistance was found by the measurement of a cavity impedance. The cavity impedance compensated coupling loss was redrawn on the Smith Chart. The loaded Q and coupling factor were obtained based on the compensated impedance locus and then the unloaded Q factor was calculated. To verify the proposed procedure, the cavity with lossless coupling was measured. The two measurement results in the lossy and lossless coupling agree well. The results confirm the proposed procedure is valid. [ABSTRACT FROM AUTHOR]

With the increasing number of wireless communication applications, the field lest environment is more and more complex, portable network analyzer can better help staff to do field lest, maintenance. In this paper, we design a low frequency vector network analyzer, which uses the sequential quadrature measurement mechanism, composes of swept signal source, reflected bridge, analog multiplier, standard calibrator and touch display etc. It can measure VSWR, impedance, reflection loss and other parameters for the devices within the 50 kHz to 60 MHz frequency range. These parameters can be displayed in the touch LCD screen. After testing, the network analyzer designed in this paper can be stable and reliable operation. [ABSTRACT FROM AUTHOR]

In this paper, compact linear dual polarized series-fed 1 × 2 linear and 2 × 2 planar arrays antennas for airborne SAR applications are proposed. The proposed antenna design consists of a square radiating patch that is placed on top of the substrate, a quarter wave transformer and 50-Ω matched transformer. Matching between a radiating patch and the 50-Ω microstrip line is accomplished through a direct coupled-feed technique with the help of an impedance inverter (λ/4 impedance transformer) placed at both horizontal and vertical planes, in the case of the 2 × 2 planar array. The overall size for the prototype-1 and prototype-2 fabricated antennas are 1.9305 × 0.9652 × 0.05106 λ0³ and 1.9305 × 1.9305 × 0.05106 λ0³, respectively. The fabricated structure has been tested, and the experimental results are similar to the simulated ones. The CST MWS simulated and vector network analyzer measured reflection coefficient (S11) results were compared, and they indicate that the proposed antenna prototype-1 yields the impedance bandwidth > 140 MHz (9.56-9.72 GHz) defined by S11 < -10 dB with 1.43%, and S21 < -25 dB in the case of prototype-2 (9.58-9.74 GHz, S11 < -10 dB) > 140 MHz for all the individual ports. The surface currents and the E- and H-field distributions were studied for a better understanding of the polarization mechanism. The measured results of the proposed dual polarized antenna were in accordance with the simulated analysis and showed good performance of the S-parameters and radiation patterns (co-pol and cross-pol), gain, efficiency, front-to-back ratio, half-power beam width) at the resonant frequency. With these features and its compact size, the proposed antenna will be suitable for X-band airborne synthetic aperture radar applications. [ABSTRACT FROM AUTHOR]

Due to lack of diagnostic and predictive to assess the effectiveness of compensation and predict the critical operation of capacitor banks, failures that lead to the correction of the power factor is not performed so occur effective. Integrating a system of data acquisition, programmable logic controller, a friendly interface and a communication protocol Modbus, when testing, the contribution of each step was obtained and determined, indirectly, its effect on the current of each one phase. The relative error obtained was 0.03 kVAr step and 1.6 kVAr for the bank, being permissible to be less than the margin of effectiveness of 75% expected to consider the step is damaged or not. The validation of the system in a real bank in operation, deviations from the expected value were within the expected range, being feasible to be applied in electrical installations lacking a monitoring and diagnostics of installed banks. [ABSTRACT FROM AUTHOR]

Coaxial coil topology is used as the transfer medium in traditional MCR-WPT (Magnetic Coupled Resonant Wireless Power Transfer) systems to improve the transfer characteristics. The intermediate coils are added to extend the transmission distance, whose positions are critical. This paper focuses on the optimal intermediate coil positions for an MCR-WPT system with four coaxial planar circular spiral coils. By modeling the MCR-WPT system, the mathematical expression of the self-inductance and the mutual inductance are used to calculate the load power of the MCR-WPT system, which is composed of four planar circular spiral coaxial coils, and using MATLAB. The optimal distance ratio between the adjacent coils for maximizing the power of load is proposed. Furthermore, the experiments are implemented from the network analyzer and the experimental platform. In the platform, the load power is measured at the different intermediate coil positions, and the optimal position at which the load power is maximized is found. Both experimental results obtained by the network analyzer and the experimental platform have validated the theoretical and simulation results and provided the correctness of the suggested ratios.

An analytical method was developed to estimate uncertainties in full two-port Vector Network Analyzer measurements, using total differentials of S-parameters. System error uncertainties were also estimated from total differentials involving two triples of standards, in the Direct Through connection case. Standard load uncertainties and measurement inaccuracies were represented by independent differentials. Complex uncertainty in any quantity, differentiably dependent on S-parameters, is estimated by the corresponding Differential Error Region. Real uncertainties, rectangular and polar, are estimated by the orthogonal parallelogram and annular sector circumscribed about the Differential Error Region, respectively. From the user's point of view, manufactures' data may be used to set the independent differentials and apply the method. Demonstration results include: (1) System error differentials for Short, matching Load and Open pairs of opposite sex standards; (2) System error uncertainties for VNA extended by two lengthy transmission lines of opposite sex end-connectors; (3) High uncertainties in Z-parameters against frequency of an appropriately designed, DC resistive, T-Network; (4) Moderate uncertainties in amplitude and phase patterns of a designed UHF radial discone antenna (azimuthally rotated by a built positioner, under developed software control of a built hardware controller) polarization coupled with a constructed gain standard antenna (stationary) into an anechoic chamber.

The objective was to study uncertainty in antenna input impedance resulting from full one-port Vector Network Analyzer (VNA) measurements. The VNA process equation in the reflection coefficient àof a load, its measurement m and three errors Es, determinable from three standard loads and their measurements, was considered. Differentials were selected to represent measurement inaccuracies and load uncertainties (Differential Errors). The differential operator was applied on the process equation and the total differential error dàfor any unknown load (Device Under Test DUT) was expressed in terms of dEs and dm, without any simplification. Consequently, the differential error of input impedance Z -or any other physical quantity differentiably dependent on ÃÂ- is expressible. Furthermore, to express precisely a comparison relation between complex differential errors, the geometric Differential Error Region and its Differential Error Intervals were defined. Practical results are presented for an indoor UHF ground-plane antenna in contrast with a common 50 Ω DC resistor inside an aluminum box. These two built, unshielded and shielded, DUTs were tested against frequency under different system configurations and measurement considerations. Intermediate results for Es and dEs characterize the measurement system itself. A number of calculations and illustrations demonstrate the application of the method.

Abstract: The authors present in this article an overview of the six port reflectometer (SPR). They realized SPR using broadside coupled lines for achieving ultrawide band, which is essential for its working as an alternative network analyzer. [ABSTRACT FROM AUTHOR]

We have developed a new algorithm for the uncertainty analysis of permittivity calculations of high-loss materials using the transmission/reflection (T/R) method. In the T/R method, several calculation procedures are performed to derive the permittivity. In our method, the permittivity is derived from measured S -parameters by solving an equation in which S -parameters are included in the form (S21+S12)+\beta (S11+S22) , where \beta is a weighted factor to be optimized to minimize the uncertainty. We confirmed its efficacy by doing numerical calculations, as well as using actual measurement data for several materials obtained with a waveguide fixture. We also considered the effect of the type of calibration method used on a vector network analyzer on the permittivity uncertainty, and quantitatively clarified that it is essential to develop a highly accurate $S$ -parameter measurement system to perform permittivity measurements using the T/R method accurately. [ABSTRACT FROM PUBLISHER]

We present a terahertz time-domain spectroscopybased setup based on photoconductive antennas and a femtosecond fiber laser for measuring the transmission S parameters of electronic devices. To this end, radiation is focused into horn antennas attached to the waveguide-coupled devices under test and coupled out of the device using a similar setup. The terahertz emitter is fiber-coupled in order to allow for flexible selection the measurement geometry. As test cases, the S21 parameters of several H band (220-330 GHz) amplifiers are measured and show promising results. Also, the response of a W band amplifier is measured, marking the lower frequency boundary for this setup. In both cases, the measurements are compared to measurements retrieved using a commercially available vector network analyzer with frequency extenders, showing rather good agreement. Transmission measurements of "thru" waveguides used as a reference imply our system's ability tomeasure up to at least 2.5 THz, widely exceeding the bandwidth of currently available network analyzers. [ABSTRACT FROM AUTHOR]

In this paper, we report an integrated single-chip surface acoustic wave sensor with the capability of measuring magnetic field, temperature, and humidity. The sensor is fabricated using a thermally sensitive LiNbO3 substrate, a humidity sensitive hydrogel coating, and a magnetic field sensitive impedance load. The sensor response to individually and simultaneously changing magnetic field, temperature and humidity is characterized by connecting a network analyzer directly to the sensor. Analytical models for each measurand are derived and used to compensate noise due to cross sensitivities. The results show that all three measurands can be monitored in parallel with sensitivities of 75 ppm/°C, 0.13 dB/%R.H. (at 50%R.H.), 0.18 dB/Oe and resolutions of 0.1 °C, 0.4%R.H., 1 Oe for temperature, humidity and magnetic field, respectively. A passive wireless measurement is also conducted on a current line using, which shows the sensors capability to measure both temperature and current signals simultaneously. [ABSTRACT FROM PUBLISHER]

We describe the development of a novel instrument intended for the measurement of the acoustical reflection coefficient of materials. The instrument effectively implements a one-port vector-corrected network analyzer in the acoustic, rather than the electromagnetic, domain. Employing the well-documented methods of error correction familiar to microwave engineers, this instrument permits automated measurement of an acoustic impedance presented to a waveguide port. A dual-directional coupler allows a working frequency range of well over an octave. In principle, a set of six couplers would allow measurement from 100 to 50000 Hz. [ABSTRACT FROM AUTHOR]

SUMMARY Technologies of small size reflectometers constructed in the form of RF functional systems in packages (SiPs) for RF testers are described. As primary concerns, focusing on the directivity and dynamic range of the reflectometer performance, we propose the construction and core circuit topologies to realize a very small reflectometer SiP that satisfies the functions of vector network analysis for RF testers. The reflectometer features a very small size, less than 1/50 of our conventional hybrid form reflectometer, and has good performance for RF testers. [ABSTRACT FROM AUTHOR]