Experimental demonstration of a 35 GHz holographic antenna
We have developed a novel two-dimensional grating antenna based on microwave holography. The two-dimensional grating (hologram) is formed on a dielectric substrate and fed by an integrated surface wave exciter. Various design issues will be presented, as will a 35 GHz demonstration prototype antenna designed, fabricated, and tested. Measured radiation patterns closely agreed with the theoretical prediction.
A Numerical Modelling Study of a Planar Holographic Antenna
.............................................................................1 Acknowledgements..................................................................6 CHAPTER 1 : INTRODUCTION ........................................................7 1.1 PRINTED HIGH GAIN MILLIMETREWAVE ANTENNAS – NEEDS AND LIMITATIONS .............................. ........................ ....7 1.2 HOLOGRAPHICALLY-BASED ANTENNA DESIGNS ....................................8 1.3 OVERVIEW OF THE THESIS ..............................................................10 1.4 REFERENCES FOR CHAPTER 1 ...........................................................10 CHAPTER 2 : REVIEW OF HOLOGRAPHICALLY-BASED ANTENNAS ......12 2.
Multi-directional spatial error concealment using adaptive edge thresholding
In this paper, a new method for spatial concealment of missing areas in image and video signals transmitted over error prone infrastructures, is presented. The concealment process is performed in three steps. First, a novel technique is used to estimate the significant edges of missing areas after performing a directional edge analysis on the correctly received neighboring blocks of the missing areas. This technique uses the moments of the neighboring edge magnitudes to obtain an adaptive threshold for rejecting non-significant directions. Second, based on the predicted significant directions, an approximation is obtained for each missing pixel. Finally, for each pixel, we compute a weighted average by using two edge correspondence measures as weighting factors. Moreover, the adaptive thresholding of the edges let us include as many edges as necessary in the interpolation process. Experiments show that the proposed method outperforms the previous state of the art methods based on both subjective and objective measures.