Electromagnetic Field Propagation Characteristics Of Ultra-wideband Analog

There are many systemic theories on decaying law of UWB electromagnetic field in vacuum and air. This work is one parts of National Science Fund, subject "A study on disaster savingness using UWB electromagnetic detect in city" (No: 40374027). For solving the problem of living security and filling vacancy in the field in our country, this paper are mainly about the simulation and study on the propagation property of UWB electromagnetic field, including: analyzing property of UWB electromagnetic field; through simulation and compute, studying given mechanism; analyzing the property of reflection and scatter of UWB electromagnetic field in different medium, completing the analysis of time domain field and decaying field of UWB electromagnetic field. At last, it compare with the ordinary radar using single frequency continuous wave as the exciting pulse. Specially, all the results are analytical of mathematical-physical equation, not the numerical solution.Studying around the propagation property of UWB electromagnetic field is involved in this paper. The problems are discussed in different extend using simulation and theories, included: radiation theory of UWB, energy density, the relationship of radiation aperture and the scatter of ideal target in different medium.1. The retarded potential is used to derive the transient radiation characterization of general space-time source distribution, based on the time domain Maxwell equation. Transient radiation is characterized by its short-time effect and can be described and represented by projection transform and impulse radiation characteristic. The finite during period of radiated electromagnetic field is decided by the time width of exciting pulse.2. Using Huygens equivalent principle, calculate the relationship between any shade of electric strength and exciting out of ultra-wide TEM antennas aperture radiation field. The conclusion is that, in radiation field, electric strength loading on long border exciting is bigger than short one at the same point.3. Base on application, study on the scattering property of UWB in vacuum and soil medium. As the UWB electromagnetic field is variant with the time going on, the incidence electromagnetic field accrues the dispersion, the frequency of incidence electromagnetic field which we got is not the same with the one of scattering electromagnetic field.