Design, fabrication, and testing of a paraboloidal reflector antenna and pulser system for impulse-like waveforms

Increasing the Focused Response of Impulse Radiating Antennas Through Polarization Control of Aperture Fields

“…Strictly speaking, the aperture height is a vector quantity, with the -component computed in the same fashion, but the symmetry of most practical IRAs forces the -component of to be zero [1]. It is worth noting that for times less than the clear time of the antenna, (1) and (2) are exact, and time domain physical optics is not an approximation [4]. The clear time of the antenna is the time until diffraction effects reach the observer and alter the ideal early-time fields.…”

“…The clear time is related to the size of the aperture and is usually on the order of , where is the dominant length of the antenna. This dominant length may be a reflector radius, a feed-arm length, or some other linear dimension that dominates 0018-926X/$20.00 © 2006 IEEE the response, depending on the specific geometry of the IRA in question [2].…”

“…It is well known that the focused response from an IRA on boresight is given approximately as (1) where is the applied voltage waveform, is the distance to the observation point, is the speed of light, , and is the aperture height given by (2) The quantity in (2) is the peak applied voltage under stepfunction excitation, and the surface integral in (2) is carried out over the area of the focused aperture. In general is a function of time, but for early times the voltage on the line and electric field in the aperture have the same temporal dependence.…”

“…That spherical wave is converted into a plane wave in the geometric optics approximation by the focusing optic. The focusing optic can be a lens or a reflector (or even a timed array), but for many practical applications, reflectors are preferable for their light weight and low volume [2]. Aperture theory (physical optics) is then used to compute the radiated far field.…”

TMax Electromagnetic Finite Difference Time Domain Simulations Cray X1 of the Impulse Radiating Antenna

“…The Air Force Research Laboratory (AFRL) Directed Energy High Power Microwave Division (DEH) performs effects assessments via the Impulse Radiating Antenna [1] (IRA) as a source for both wideband and narrowband experiments. Understanding how the IRA launches electromagnetic radiation can assist with optimal design configuration to provide more energy at a desired frequency range.…”