in this paper, by considering a squint angle for synthetic aperture radar in the strip-map mode, a method is proposed for estimating parameters of a fixed acceleration moving target. non-zero doppler centroid and range-azimuth coupling in the squint mode add complexity to estimation equations of moving target parameters and cause doppler ambiguity. this, in turn, causes to lose the efficiency o...

With a proper design, the aperture field of a conventional radial waveguide pin-fed non-resonant array antenna (RWPFAA) can be rendered equiphase at a given central frequency. However, when the operating frequency deviates from this central frequency, the aperture field will exhibit an undesired conical phase error. To alleviate this problem, we propose a novel design in which the frequency-dep...

Space-to-ground optical communication systems can benefit from reducing the size, weight, and power profiles of space terminals. One way of reducing the required power-aperture product on a space platform is to implement effective, but costly, single-aperture ground terminals with large collection areas. In contrast, we present a ground terminal receiver architecture in which many small less-ex...

The theories of Pulgram (1970) suggest that if the vowel of a French syllable is open then it will induce syllable segmentation responses that result in the syllable being closed, and vice versa. After the empirical verification that our target French-speaking population was capable of distinguishing between mid-vowel aperture, we examined the relationship between vowel and syllable aperture in...

Precise knowledge of the area of apertures used in high precision radiometry is extremely important. A method is presented here for the determination of the area of round and irregularly shaped apertures by comparison to a standard aperture which has been measured by other means to high accuracy. The method presented here is quick and has no physical contact with the fragile edge of the apertur...

An interferogram produced by wide-aperture interferometers is studied both theoretically and experimentally. The fringe spacing is shown to increase nonlinearly with the numerical aperture and the fringe envelope to become narrower as the numerical aperture is increased. Phase measurements with wide-aperture interferometers therefore require calibration, and the phase can be measured only over ...

In this paper, we optimize the size of aperture and number of sensors for Wideband Covariance Matrix Sparse representation (W-CMSR) method for Wideband Direction of Arrival estimation using Simulated Annealing. The performance of W-CMSR is obtained with initial number of sensors and aperture size. Then, we find the performance of W-CMSR with optimized number of sensors and aperture size using s...

Pollen grains display a wide range of variation in aperture number and arrangement (pattern) in angiosperms. Apertures are well-defined areas of the pollen wall surface that permit pollen tube germination. For low aperture numbers, aperture patterns are characteristic of the major taxonomic divisions of angiosperms. This paper presents a developmental model that explains most of the aperture pa...

The EMBRACE is denoted as the Electronic Multi-Beam Radio Astronomy ConcEpt which is planned as two aperture arrays with multiple independent Field of View (FoV) capabilities. A 300 square metre aperture array will be based in Westerbork close to the Westerbork Synthesis array and a second 100 square metre aperture array will be based in Nancay. The main objectives of EMBRACE are to demonstrate...

We report on a pixel whose aperture can be varied electrically. The pixel is confined by a hole-patterned polymer wall and a dielectric liquid forms a ring shape around the wall surface. Without an electric field, the pixel has the largest aperture. The applied fringing field stretches the liquid surface, leading to a decrease in the aperture size. The switchable aperture ratio of the pixel is ...