graphene nanostructures were synthesized by hummer method. 1, 3, 5 and 7 wt% of graphene nanostructures were suspended in certain amount of acetone on a mechanical stirrer and stirred then added to epoxy resin. after 4 hours, solution and graphene platelets (gps) were prepared. nanostructures were characterized by x-ray diffraction (xrd), scanning electron microscopy (sem ), fourier transform i...

In this report we discuss the mechanisms of cognitive radar. This report is organized as follows: We start with the history of cognitive radar, where origins of the PAC, Fuster?s research on cognition and principals of cognition are provided. Fuster describes five cognitive functions: perception, memory, attention, language, and intelligence. We describe the Perception-Action Cyclec (PAC) as it...

Compressive sensing (CS) provides a new paradigm in data acquisition and signal processing for radar. In this work, we investigate the performance of several deterministic waveforms for the basic problem of range-only estimation in CS-radar system. We investigate the effects of a digital RF system from signal generation at the transmitter, to sparse signal recovery at the receiver, on the incoh...

This paper, describes a novel technique that detects a driver’s state using Ultra Wide Band(UWB) radar. UWB radar can measure both human vital signs and movement simultaneously with just one device. It is an improvement on existing Driver State Monitoring(DSM) systems because is much cheaper and lighter. And UWB radar can be used all day and night in all weather conditions without contacting th...

In the early days of radar, range resolution was made by transmitting a short burst of electromagnetic energy and receiving the reflected signals. This evolved into modulating a sinusoidal carrier into transmitting pulses at a given repetition interval. To get higher resolution in the radars the transmitted pulses got shorter and thereby the transmitted spectrum larger. As will be shown later t...

Spectrum sharing between radars and cellular systems is an emerging area of research. In this paper, we model channel between a seaborne MIMO radar and MIMO cellular system. We model a 2D channel to capture the azimuth aspect of the spectrum sharing scenario. Our channel modeling methodology allows MIMO radar to place accurate nulls in the azimuth location of base stations (BS), thus, protectin...

Bistatic pulse-Doppler airborne radar has desirable properties such as the low probability of detection by other radars relative to its monostatic counterpart. However, the clutter characteristics of bistatic airborne radar are more complex than those of monostatic airborne radar. The clutter spectra not only vary severely with range, but also vary with bistatic configuration. In this article, ...

The melting layer (ML) is a significant phenomenon in weather radar observations. It consists of initially frozen hydrometeors falling into air below the 0C isotherm (freezing level) where they start melting. The radar echoes from melting hydrometeors differ from those from rain droplets as well as from frozen hydrometeors, and ML is observed as the radar bright band. The ML is a complex atmosp...

Characteristic signatures are often observed in HF radar range-time-intensity plots when travelling ionospheric disturbances (TIDs) are present. These signatures, in particular the variation of the F-region skip distance, have been synthesised using a ray tracing model. The magnitude of the skip variation is found to be a function of the peak electron density perturbation associated with the TI...

In this paper, an analysis of radar range and probability of detection by the use of multiple-input multiple-output (MIMO) radar with cooperative high altitude aeronautical platforms (HAAP) relay (which could operate at stratospheric altitudes) is presented. In this study, a method of cooperative diversity known as ampliy-and-forward (AF) is considered and a target fluctuation model (Swerling I...