Mutual coupling has always been a drawback for array antennas with different configurations. Engineers are obliged to cope with negative effects of mutual coupling in designing procedure. The most important cause of the mutual coupling is surface wave propagation as it transfers the wave in undesirable directions. A method to reduce this effect is the suppression of surface waves using metamaterial structures. A known type of metamaterial used for this purpose is complementary of split ring resonator (CSRR). In this work, a structure consisting of CSRRs with wires is used to alleviate the effect of mutual coupling. The results are verified by calculating effective permeability and permittivity of the structure showing the Mu‐negative property. The calculation is also performed by Kramers‐Kronig relations. A 17 dB reduction in mutual coupling is achieved over a bandwidth range of 170 MHz.

In this paper, a graphene-based reflectarray antenna using ENZ (Epsilon-Near-Zero) metamaterial at terahertz (THz) band is proposed, and the performance of its unitcell is investigated. Then, the phase distribution and radiation pattern of the antenna are examined. Benefiting from exceptional complex surface conductivity of graphene which is a novel 2-d material, the size reduction of reflectarray has been facilitated as a result of plasmonic mode propagation within the structure which in turn leads to an increase in propagation constant. Moreover, tunneling phenomenon in ENZ material, a kind of metamaterial which has a relative permittivity under 1, helps reduce the loss. Taking advantage of these outstanding features of both materials, the proposed reflectarray is designed to function at 1 THz and is composed of 150 × 150 elements with square-shape configuration. We have achieved 40 dB of gain using the combination of graphene and ENZ material in reflectarrays, and also it is the first time that they are used together in the reflectarray. This work mainly focuses on the impact of using ENZ material and graphene simultaneously which is not done before, then the results demonstrate that it has a considerable effect on increasing the reflectarray gain.

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In this paper, the viability of MEMS accelerometers is investigated to measure vibration parameters related to different locations of a vehicle with respect to the automotive dynamic functions. The data is collected to compare the accelerometer performances in different locations on the vehicle, including on the hood above the engine, on the hood above the radiator fan, over the exhaust pipe, and on the dashboard. The power spectral density (PSD), together with the time and frequency domain results, confirm the strength and frequencies of the sources of vehicle dynamics. The frequencies obtained from the vibrations of the hood above the engine and radiator fan are approximately 44.18 Hz and 38 Hz, respectively. In terms of the vibration amplitude, the measured amplitudes are between 0.5 g and 2.5 g in both cases. Furthermore, the time domain data collected on the dashboard during driving mode reflects the road condition. Overall, the knowledge obtained from the various tests conducted in this paper can be advantageous for further control and development of vehicle diagnostics, safety, and comfort.

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