We will also study the inclusion of absorbing material near the junction of the feed arms with the reflector, and the inclusion of edge treatments to reduce the sidelobe level. Additional information is available here . We have successfully developed a collapsible IRA with a four-foot diameter, that is lightweight, highly portable, and rugged. In addition, this device has low wind loading because the reflector is built from a conducting mesh fabric. This device has a FWHM impulse of 70 ps, and is effective from 100 MHz to 7 GHz.
Additional information is available here .
Time Domain Antenna Ranges Time domain antennas ranges can be used to obtain antenna pattern data much more economically than frequency domain ranges. A waveguide with a graded index can support a TEM wave around a bend with constant angular velocity, but it is challenging is to build such a material. We have demonstrated a waveguide bend fabricated from machined layers of polybutyldiene loaded with varying amounts of titanium dioxide. Our model had a FWHM impulse response of 70 ps in a waveguide bend with 2 inch cross section and 6 inch outer radius. By switching the polarity of a ferroelectric ceramic, one can inject a cloud of electrons into a stream of fast-moving gas, slightly upstream of the switch location.