Abstract: A conical horn antenna is disclosed having dual dielectric bands mounted therein for improving the rotational symmetry or elipticity of the radiated beam as well as the efficiency. The first and second dielectric bands are coaxially mounted to each other and to the conical horn. The lengths of the bands are determined by the frequencies being propagated. A circularly polarized dominant wave such as TE.sub.11 mode is applied to the antenna and excites a series of higher order waves such as the TM.sub.11 mode. The circularly polarized dominant and the higher order modes are propagated toward the aperture where they are in phase and therefore add vectorially. The dual dielectric band acts as a slow wave structure and higher order waves which in turn provide an improved phasing between the dominant modes.

Abstract: A horn antenna is disclosed having a built-in circular polarizer and a cross polarization attenuator. A square-apertured horn antenna has a plurality of pairs of conductive fins disposed along opposite edges of the horn interior. The individual fins are separated from each other by approximately one-fourth wavelength. The fins are at a 45 degree angle to that linear wave and react with that linear wave by imparting a circular rotation to that wave as the wave propagates past each pair of fins. A stepped attenuator is mounted in the input section to the horn antenna perpendicular to the linear input wave. The attenuator substantially absorbs cross-polarized signals whether reflected from the aperture of the horn or provided by the incoming signal.

Abstract: A lightweight microwave filter device is disclosed which utilizes a housing made of a lightweight metal such as aluminum having a relatively large coefficient of thermal expansion. The microwave filter also utilizes resonator elements which are either interdigital or in a comb-line filter arrangement. The resonator rods are made in two segments -- a lightweight metal such as aluminum having a relatively large coefficient of thermal expansion and a metal having a very low coefficient of thermal expansion such as invar. As the temperature varies the length of the rod also varies. The tuning capacitance between the rods and the housing varies with temperature changes and compensates for the change in the rod length. Thus the resonant frequency of the microwave filter is maintained relatively constant over a predetermined temperature range.

Abstract: A realistic laser weapon simulator is disclosed which utilizes a laser transmitter in combination with a rifle for teaching marksmanship by firing laser "bullets" at an infrared detector equipped target. The laser weapon includes a piezoelectric crystal coupled to a laser in a housing for mounting axially to a rifle barrel. The rifle may develope a mechanical force by firing a blank cartridge which generates a shock wave and vibrates the piezoelectric device. A mechanical force may also be applied directly to the piezoelectric device by the rifle's hammer.