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The application of UHF radio-frequency identification (RFID) systems is rapidly increasing. However, because band near the frequency for the UHF-RFID system is also used with the cellular phone, the influence on UHF-RFID system is worried. Prepare the Faraday cage is easy to solve this problem, but generally it shields external noise frequency by broadband. So, It makes difficult to using wireless...
Stretchable, flexible and tunable RF devices that are fabricated with Polydimethylsiloxane (PDMS) Electrically Conductive Composites (ECC) are presented. Using this composite material allows mechanical modulation of the device dimensions resulting in tuning of its frequency response. A planar loop antenna and a 5th order stepped impedance low pass filter operating around 1.5 GHz with tunability greater...
A phenomenological approach is developed to identify the physical parameters causing the dc-voltage-induced tunability of aluminum nitride (AlN) acoustic resonators, widely used for RF filters. The typical resonance frequency of these resonators varies from 2.038 GHz at -200 V to 2.062 GHz at +200 V. This indicates, based on these RF measurements versus dc bias and the model used, that the AlN stiffness...
In this paper, aluminum nitride (AlN) Lamb wave resonators (LWR) operating in air from room temperature up to 600??C are demonstrated for the first time. To date, no AlN RF devices have been tested and characterized at extreme temperatures. This paper describes the design, fabrication and characterization of temperature compensated AlN Lamb wave resonators at 600??C. Temperature coefficients of frequency...
Electrochemical reactions occuring at high temperatures and inside bulk materials are often observed indirectly. For instance, one commonly estimates the state of the three-way catalyst (TWC) in the exhaust pipe of a gasoline engine from the measured air-to-fuel ratios in the exhaust gases entering and leaving the catalyst. Our goal is to directly observe the catalyst state in situ by a non-contact...
In this paper, the authors present the design and implementation of a microwave oscillator circuit with ultra-fast amplitude control for an inspection system appropriate for real-time measurements of continously streaming materials. The material passing through the resonator of the oscillator changes the resonance frequency and the quality factor of the resonator. This influences the oscillation frequency...
In this paper, we present a novel ultra-fast material inspection system for continuously streaming dielectric materials, such as paper, plastic films, non-aqueous liquids etc. The material stream is being passed through a cavity resonator whose electrical parameters are altered by the presence of the material, due to its interaction with the electric field inside the resonator. The latter is employed...
We have developed an electromagnetic cavity resonator based RF sensor for online determination of granular dielectric materials weight. This sensor is non-instrusive and detects the density of the granular materials using resonant peaks captured instantaneously. A laboratory prototype of the RF sensor has been constructed. The properties of the RF cavity were simulated by ANSYS, and confirmed using...
This paper is the first of two that present analytical and numerical analysis of high power and ultra wide band radars interacting with EMI and radar suppression materials. Magnetic materials are often used in isolators, thin film EMI materials and/or appliques. Such magnetic composites may be exposed to wide band and/or high power signals in operational radar systems. We describe exotic interactions...
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