Basic principle of ultrasound medical imaging is a direct adaptation of that of phased array radar. Modern ultrasound scanners use large either linear or phased array of piezoelectric (PZT, for instance) transducers. Designing electronic beam-forming network for ultrasound pulsed echo system is thus very much similar to the adaptive antenna array system design in a different modality. When ultr...

Imaging or beam-steering systems employing a periodic array of microlenses or micromirrors suffer from diffraction problems resulting from the destructive interference of the beam segments produced by the array. Simple formulas are derived for beam steering with segmented apertures that do not suffer from diffraction problems because of the introduction of a moving linear phase shifter such as ...

We demonstrate coherent random lasing from an aerosol of dye-doped microdroplets in air. The aerosol is in the form of a linear array of polydisperse, arbitrarily shaped, and randomly spaced microdroplets with average dimensions of about 30 μm. Upon optical excitation, ultranarrow lasing modes were observed in the emission along the axis of the linear array, while the transverse emission exhibi...

Abstract Due to the huge data storage and transmission pressure, sparse collection strategy has provided opportunities challenges for 3D SAR imaging. However, brought by linear array will produce high-level side-lobes, as well aliasing false-alarm targets. Simultaneously, vectorizing or matrixing of makes high computational complexity memory usage, which is not practicable in real applications....