Numerical methods for modeling of radar wideband signal scattering by aerial, ground and subsurface objects
In our review the developed electrodynamic numerical methods for modeling of scattering characteristics of complex-shaped electrically large and resonant radar objects are considered. Futures of mentioned numerical algorithms and their advantages in comparison with other well known techniques are discussed. Proposed algorithms allow obtaining frequency responses of air, ground, and subsurface radar objects for given sounding conditions. Particular qualities of object ultrawideband impulse response modeling are also briefly discussed. In conclusion we demonstrate some results of numerical modeling of ultrawideband impulse responses of different air, ground, and subsurface objects in VHF, UHF, and SHF bands. Such results have a wide field of application for solving applied problems at the stage of development of effective wideband radars of different types.
Unified fast numerical algorithm for calculation of EM field of dipole located at arbitrary distance from the boundary of dielectric media
An algorithm is considered for calculating the EM field of dipole in case of arbitrary spacing between the point of dipole location and the point of its field observation, as well as arbitrary distance of points from the boundary of dielectric half-spaces. The algorithm is adapted to the height of mentioned points above the boundary and allows to reduce significantly calculation time while providing given accuracy of the dipole EM field component calculation. Results of calculation of radar scattering characteristics are demonstrated for low-altitude and ground objects obtained using the developed calculation technique based on integral equation solution, and using proposed algorithm for dipole EM field calculation.
Ultrawideband radar
The author discusses the characteristics of ultrawideband radar and makes qualitative comparisons with narrowband systems. He notes that ultrawideband radars use signal bandwidths greater than 25% of center frequency. Conventional radio and radar signal bandwidths are generally less than 1% of center frequency. Using ultrawideband signals gives a range resolution smaller than most military targets. It is further pointed out that ultrawideband impulse signals can provide a capability for target imaging and identification through resonance characteristics. The added capabilities gained through ultrawideband signals are balanced by needs for complex receiver and signal processing.<<ETX>>