Kassam, Saleem
Email Address
ORCID
Disciplines
Search Results
Now showing 1 - 4 of 4
Publication Design and Implementation of Near-Field, Wideband Synthetic Aperture Beamformers(2004-01-01) Ahmad, Fauzia; Frazer, Gordon J.; Kassam, Saleem A; Amin, Moeness G.A coarray-based near-field, wideband synthetic aperture beamformer using stepped-frequency signal synthesis and post-data acquisition processing is presented. While coarray techniques offer significant reduction in the number of array elements for a given angular resolution, the hybrid subarray-stepped frequency realization of wideband systems simplifies implementations and offers flexibility in beamforming. Proof of concept is provided using real data collected in an anechoic chamber for several pulse shapes and array weightings.Publication Statistical characteristics of the envelope in diversity combining of two correlated Rayleigh fading channels(2007-06-01) Tang, W; Kassam, SaleemPerformance of diversity systems is often evaluated under the assumption of perfect interleaving and characterised in terms of long-term parameters such as the average bit-error rate, which does not capture the dynamics of fading channels. Statistical characteristics (static and dynamic) of the envelope of two correlated Rayleigh fading channels are explored using a physical model. For two popular diversity-combining schemes, maximal ratio combining and selection combining, both static and dynamic (level-crossing rate) properties of correlated fading channels are derived. These results are very useful for performance evaluation of diversity systems without bit-level simulations. The results can also provide very useful characteristics such as average duration of fades, fading rate and outage probability for two-channel diversity systems and can be extended to multiple fading channels.Publication A Wideband, Synthetic Aperture Beamformer for Through-The-Wall Imaging(2003-10-14) Ahmad, Fauzia; Amin, Moeness G.; Kassam, Saleem A; Frazer, Gordon J.A coarray-based aperture synthesis scheme using subarrays and post-data acquisition beamforming is presented for through-the-wall wideband microwave imaging applications. Various effects of the presence of the wall, such as refraction, change in speed, and attenuation, are incorporated into the beamformer design. Simulation results verifying the proposed synthetic aperture technique for a TWI system are presented. The effects of incorrect estimates of the parameters of the wall, such as thickness and dielectric constant, on performance are investigated.Publication A New Approach for Near-Field Wideband Synthetic Aperture Beamforming(2003-04-06) Ahmad, Fauzia; Frazer, Gordon J.; Kassam, Saleem A; Amin, Moeness G.A coarray-based synthetic aperture beamformer using stepped-frequency signal synthesis and post-data acquisition processing is presented for wideband imaging of near-field scenes. The proposed beamformer formulation and implementation finds key applications in through-the-wall microwave imaging and landmine detection problems. While coarray techniques offer significant reduction in array elements for a given angular resolution, stepped-frequency realization of wideband systems simplifies implementation and offers flexibility in beamforming. Proof of concept is provided using real data collected in an anechoic chamber.