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This paper suggests the usage of an optimized structure of the embedded wafer-level ball grid array technology for millimeter-wave antennas-in-package. Multiple antenna arrays in a second redistribution layer have been designed, evaluated, and integrated with different transceivers to form very compact sensor packages for 61- and 122-GHz radar applications. The resulting packages contain a complete radar front end while featuring dimensions of $8\,\,\text {mm}\times 8~\text{mm}$. The packages are easy to assemble and replaceable. Theoretical considerations, numerical results, and measurements have been carried out for the single components. For the verification of the sensor packages, a system demonstrator was developed, and measurements have been performed in continuous-wave mode. At both frequencies, promising system performance regarding range and distance errors could be confirmed without the usage of complex processing and calibration algorithms. [ABSTRACT FROM AUTHOR]

RapidScat is a National Aeronautics and Space Administration (NASA) Ku-Band scatterometer that was operated onboard the International Space Station between September 2014 and August 2016 when the mission effectively ended after an irrecoverable instrument failure. A unique non-Sun-synchronous orbit facilitated global contiguous geographical sampling between the ±56˚ latitude. For the first time, such an orbit enabled an overlap with other scatterometers flying in Sun-synchronous orbits. The double-difference technique was developed and successfully used for microwave radiometer calibration at the Remote Sensing Laboratory at the University of Central Florida, USA. This paper presents the extension of the double difference methodology to scatterometry. The methodology has been adopted for the cross-instrument calibration between RapidScat and QuikScat scatterometers simultaneously orbiting the Earth on-board two independent satellite platforms. The double-difference technique was deployed to compare measurements from these two scatterometers, as a more accurate alternative to the classic single difference approach. The work summarized in this paper addressed a cross-calibration algorithm developed and applied to RapidScat and QuikScat data in the period from January 2015 to March 2016. The initial results of the statistical analysis and biases between the two scatterometers are presented. Calculated biases may be used for measurement correction and reprocessing. [ABSTRACT FROM AUTHOR]

Microwave technology plays a more important role in modern industrial sensing applications. Pushed by the significant progress in monolithic microwave integrated circuit technology over the past decades, complex sensing systems operating in the microwave and even millimeter-wave range are available for reasonable costs combined with exquisite performance. In the context of industrial sensing, this stimulates new approaches for metrology based on microwave technology. An old measurement principle nearly forgotten over the years has recently gained more and more attention in both academia and industry: the six-port interferometer. This paper reviews the basic concept, investigates promising applications in remote, as well as contact-based sensing and compares the system with state-of-the-art metrology. The significant advantages will be discussed just as the limitations of the six-port architecture. Particular attention will be paid to impairment effects and non-ideal behavior, as well as compensation and linearization concepts. It will be shown that in application fields, like remote distance sensing, precise alignment measurements, as well as interferometrically-evaluated mechanical strain analysis, the six-port architecture delivers extraordinary measurement results combined with high measurement data update rates for reasonable system costs. This makes the six-port architecture a promising candidate for industrial metrology. [ABSTRACT FROM AUTHOR]

We present preliminary results from a method for estimating the optimal effective permittivity for reconstructing microwave-radar images. Using knowledge of how microwave-radar images are formed, we identify characteristics that are typical of good images, and define a fitness function to measure the relative image quality. We build a polynomial interpolant of the fitness function in order to identify the most likely permittivity values of the tissue. To make the estimation process more efficient, the polynomial interpolant is constructed using a locally and dimensionally adaptive sampling method that is a novel combination of stochastic collocation and polynomial chaos. Examples, using a series of simulated, experimental and patient data collected using the Tissue Sensing Adaptive Radar system, which is under development at the University of Calgary, are presented. These examples show how, using our method, accurate images can be reconstructed starting with only a broad estimate of the permittivity range. [ABSTRACT FROM AUTHOR]

ABSTRACT This article presents simulation and hardware implementation of a low cost radar that can be used as a speed sensor or a metal detector. The overall hardware costs only U.S. $25 and has maximum free space range of 3.65 m. Its underground range is 4.3 cm under wet soil conditions with free space distance of 50 cm above ground. The proposed model provides a basis for designing a mine detector based on the amplitude of the reflected wave. As the frequency of the wave or the water content of the ground increases, the amplitude of the reflected wave decreases making the detection difficult. A comparison between different attenuations offered to the signal under different soil conditions and different Target's materials is presented. The frequency selected for the design implementation was 10.525 GHz. A speed sensor module, HB100 miniature microwave motion sensor was used to sense the reflected wave and was interfaced with a frequency meter implemented using a microcontroller. The module transmitted a continuous wave with amplitude of 15 dBm. The wave reflected from the target was received by module's receiving antenna. It was amplified using a noninverting amplifier and was converted to pulses using a comparator. These pulses were fed to the in-house microcontroller-based frequency meter, and the speed of the target was observed on the LCD interfaced. Complete ground modeling for different water content and free space modeling was also done. The proposed model provides a low cost stand-alone implementation of the overall radar. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2484-2489, 2014 [ABSTRACT FROM AUTHOR]

Abstract: The authors have investigated an adaptive neuro fuzzy inference system (ANFIS) for the estimation of hydrometeors from the TRMM microwave imager (TMI). The proposed algorithm, named as Hydro-Rain algorithm, is developed in synergy with the TRMM precipitation radar (PR) observed hydrometeor information. The method retrieves rain rates by exploiting the synergistic relations between the TMI and PR observations in twofold steps. First, the fundamental hydrometeor parameters, liquid water path (LWP) and ice water path (IWP), are estimated from the TMI brightness temperatures. Next, the rain rates are estimated from the retrieved hydrometeor parameters (LWP and IWP). A comparison of the hydrometeor retrievals by the Hydro-Rain algorithm is done with the TRMM PR 2A25 and GPROF 2A12 algorithms. The results reveal that the Hydro-Rain algorithm has good skills in estimating hydrometeor paths LWP and IWP, as well as surface rain rate. An examination of the Hydro-Rain algorithm is also conducted on a super typhoon case, in which the Hydro-Rain has shown very good performance in reproducing the typhoon field. Nevertheless, the passive microwave based estimate of hydrometeors appears to suffer in high rain rate regimes, and as the rain rate increases, the discrepancies with hydrometeor estimates tend to increase as well. [Copyright &y& Elsevier]

Falling snow is an important component of global precipitation in extratropical regions. This paper describes the methodology and results of physically based retrievals of snow falling Over land surfaces. Because microwave brightness temperatures emitted by snow-covered surfaces are highly variable, precipitating snow above such surfaces Is difficult to observe Using window channels that occur at low frequencies (v < 100 GHz). Furthermore, at frequencies v ≤ 37 GHz, sensitivity to liquid hydrometeors is dominant. These problems are mitigated at high frequencies (v > 100 GHz) where water vapor scree s the surface emission, and sensitivity to frozen hydrometeors is significant. However, the scattering effect of snowfall In the atmosphere at those higher frequencies is also impacted by water vapor In the upper atmosphere. The theory of scattering by randomly oriented dry. snow particles at high microwave frequencies appears to be better described by regarding snow as a concatenation of "equivalent" ice spheres rather than as a sphere with the effective dielectric constant of an air-ice mixture. An equivalent sphere snow scattering model was validated against high-frequency attenuation measurements. Satellite-based high frequency observations from an Advanced Microwave Sounding Unit (AMSU-B) instrument during the March 5-6, 2001 New England blizzard were used to retrieve snowfall over land. Vertical distributions of snow, temperature, and relative humidity profiles were derived from the Mesoscale Model (MMS) cloud model. Those data were applied and modified In a radiative transfer model that derived brightness temperatures consistent with the AMSU-B observations. The retrieved snowfall distribution was validated with radar reflectivity measurements obtained from a ground-based radar network. [ABSTRACT FROM AUTHOR]

The potential of a continuous-wave microwave transceiver as a tool for detecting breathing and heartbeat of people buried in snow has been experimentally evaluated. The breathing has been clearly detected through a 1.8-m-thick snow barrier as well as through the 1.2-m-thick roof of an igloo dugout to simulate the experimental conditions of a human being trapped under an avalanche. [ABSTRACT FROM PUBLISHER]

In this paper, the authors propose continuous-wave single-frequency (CW-SF) and multi-frequency (CW-MF) microwave techniques for measurement of large-structure vibration. Theoretical background and experimental results of tests on a vertical steel structure, subjected both to artificial solicitation through a vibrodyne and to wind, are reported. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 216–218, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10874 [ABSTRACT FROM AUTHOR]