New Microwave Window Results in Better All-Around Systems

  • Published
  • By Heyward Burnette
  • Materials and Manufacturing
WRIGHT-PATTERSON AIR FORCE BASE, Ohio --  Air Force Research Laboratory scientists and engineers and Voss Scientific have successfully developed a high-power microwave vacuum/pressure interface using a broadband design that provides excellent multipactor mitigation. This new window design substantially improves the ruggedization and maintainability of existing and future microwave systems by reliably isolating radiating antennas from the source region.

Using this new high-power microwave window design reduces the size and complexity of the microwave system while increasing the power handling capability to levels exceeding the maximum available from the existing state-of-the-art test system. The reliability of the microwave system is improved by allowing insulating gas to be substituted for ultra-high-vacuum, throughout the volumes of antennas and their connecting waveguides. A more rugged, portable system, capable of handling the highest power microwave sources currently available, results from use of the window technology.

The ideal vacuum window should pass virtually all incident power with sufficiently low levels of power returned back to the microwave source such that source operation is not negatively affected. Typically it is desirable for the window to reflect less than 1 percent of the incident power to meet this criterion. To accommodate wider bandwidth HPM sources, it is desirable to maintain this small reflection coefficient over the entire waveguide band. The window developed by AFRL / Voss Scientific meets these requirements, demonstrating less than 1% reflection across the entire WR650 bandwidth of 1.12-1.7 GHz.

The high power microwave window demonstrates a robust technology that enables virtually any high power microwave system whose output is in fundamental mode rectangular waveguide to achieve reduced weight and size. The window was tested and demonstrated in WR650 waveguide (1.1-1.7 GHz), but is readily extendable to lower and higher frequency bands, as desired.