Sreeaman Rajan

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Direction finding (DF) techniques based on a circular array of monopoles or dipoles have the advantage of being able to provide unambiguous direction of arrival (DOA) estimates over 360 degrees. Of the various implementation approaches that are possible, the Adcock direction finder (ADF) is commonly used at UHF and lower frequency ranges. One of the(More)
Practical antenna array designs generally require that the elements are separated by electrically short distances. The resultant mutual coupling often adversely affects the achievable performance. Various methods are available to quantify the effects of mutual coupling in arrays and improve performance through mutual coupling compensation. Mutual coupling(More)
The simulation and practical implementation of the widely used FFT summation CFAR (constant false alarm rate) detector are both dependent on the accurate computation of the normalized detection threshold, T<sub>n</sub>. This is generally computed using numerical procedures. However, unless the number of FFT bins assigned to each channel and the number of(More)
In many applications such as localization, there is a need to determine the unknown time shift D between a signal, and its time shifted version. Aligning one against the other until the two match will find D. When working with compressive sensing (CS) measurements, only linearly transformed samples of the signal and its time-shifted version are available.(More)
The theory, design, fabrication, and measurement of new uniform circular arrays (UCAs) for direction of arrival (DOA) estimation is presented in this report. In particular, the effect of directional antenna elements in UCAs for DOA estimation is studied in detail. While the vast majority of previous work assumes isotropic antenna elements or omnidirectional(More)
A fiber specklegram sensor for multichannel sensing is presented. Analyses and experiments show that a fiber specklegram sensor (FSS) is highly sensitive to the modal phasing variation of a multimode-sensing fiber. It is shown that the FSS is less vulnerable to environmental factors than the two-arm interferometric fiber-sensing technique. Because the FSS(More)
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