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Posts tagged ‘waves’
Acoustic waves play many everyday roles – from communication between people to ultrasound imaging. Now the highest frequency acoustic waves in materials, with nearly atomic-scale wavelengths, promise to be useful probes of nanostructures such as LED lights.
However, detecting them isn’t so easy.
Continue reading ‘Visualizing Atomic-Scale Acoustic Waves In Nanostructures’ »
Antennas serve as transducers between electromagnetic waves traveling in free space and guided electromagnetic signals in circuits. As such, they play a critical role in the performance of wireless communication systems. With the proliferation of mobile wireless services that deliver voice and/or data in smaller and smaller devices, the task to design an antenna for a portable unit that meets not only operational requirements but also aesthetic and packaging restrictions is becoming more and more challenging. As result, engineers rely on a combination of theory, simulation, and experimental investigation to arrive at a design that meets all the demands of a particular application.
The basic parameters of antenna are impedence, mismatch and ohmic efficiency, radiation pattern and polarization, directivity, gain and equivalent isotropically radiated power, and effective height and aperture. In addition, celebrated Friis equation is and equations for the signal to noise ratio (SNR) of an antenna and source-field relationships are also important.For a more detailed treatment of the material pointed out here, the reader is referred to “A HANDBOOK OF ANTENNA IN WIRELESS COMMUNICATION” OF CRC Press by Lal Chand Godara.
