Abstract: A precision, waveguide-configured, bandstop filter comprises a substrate formed of a conductive material capable of being die cast. To facilitate manufacture and assembly, the substrate is preferably formed as a pair of symmetrically shaped substrate halves which, when mated together, define an interior filter structure that performs the required bandstop filter function. Each substrate half is configured to have a generally longitudinal slot that extends from a planar mating surface and effectively forms one half of an interior longitudinal waveguide section through the filter. Transverse to and located at spaced apart locations along the longitudinal slot are a plurality of channels, which define parallel conductive surface webs that extend from opposite sidewalls of the longitudinal slot. The channels serve as distributed, diametrically opposed pairs of lumped parameter tuning elements of the bandstop filter. A first end of each web forms a portion of a conductive sidewall of the longitudinal slot.

Abstract: The middle stage of a Marie-type mode launcher is configured by sliding together a pair of reusable multi-wedge shaped mandrels which, when placed together in the direction of the longitudinal axis of the launcher, form a compound mandrel from which a TE.sub.20 rectangular to crossed TE.sub.20 rectangular stage may be electroformed. One mandrel has a first double wedge-shaped section that tapers from a rectangular open end (that joins with the rectangular output end of the first stage) to an edge that is effectively diagonally located between opposing vertices of intersecting surfaces of adjacent pairs of four tapered sections that form the `X`-shaped open output end of the middle stage. The taper of the first section is a dual taper, in directions parallel with the sides of the rectangular input end of the middle stage.

Abstract: A waveguide expansion joint for connecting two circular waveguides operating in the TE.sub.01 mode while allowing for waveguide expansion and contraction due to temperature variations. The expansion joint includes first and second rings on the outside surface at one end thereof. When the expansion joint is inserted into a waveguide the rings are proximate to the inside diameter of the waveguide for absorbing undesired propagating modes, for pressurization of the expansion joint, and for coaxially aligning the waveguide and the expansion joint.

Abstract: The first section of a Marie'-configured TE.sub.10 rectangular mode to TE.sub.01 circular mode waveguide launcher is modified to provide an effectively true linear taper for the injected TE.sub.10 mode wave to the emitted TE.sub.20 mode wave. As a result, the first section is well matched at the low end of the frequency band as well as being resonance free to frequencies above the upper end of the band of interest. According to this modification, rather than have a single taper for the triangular shaped lower portion of the first section, the lower triangular portion has a second taper extending from the intersection at the lower wall of the input to the height of the exit wall at the output. This second taper provides an effective true linear taper for the input section.

Abstract: A variable ratio power combiner employs, as its major coupling component, one or more septum polarizers and associated 90.degree. differential phase shifters or quarter waveplates in place of conventional OMTs. Advantageously, a septum polarizer is a relatively simple component that serves the same function as an OMT and polarizer combination. Because it has an essentially T-shaped configuration, it can bring a pair of waveguide arms together in the same plane back-to-back, so that the resulting power combiner may provide the desired symmetrical coupling. Normally the variable ratio power combiner requires only symmetrical inputs for the sources and not both symmetrical inputs and outputs, so that only a single septum polarizer and associated quarter waveplate are employed, with an OMT used for the output. For a completely symmetrical configuration, however, the other OMT may be replaced by a separate septum polarizer/rotatable quarter waveplate arrangement.

Abstract: A dichroic antenna scanner is comprised of transmission or reflection surfaces that impart to an incoming wave a phase shift which varies across the surface of the antenna. For this purpose, a multilayer dichroic structure may be configured to have a controlled tapered spacing between the various layers or a variable reflectance across the dichroic surface, thereby varying the cut-off frequency of the dichroic surface across its surface. Since the phase of a transmitted or reflected wave varies rapidly in the vicinity of the cut-off frequency, a variation in the cut-off frequency across the dichroic surface yields a varying phase characteristic across the antenna.

Abstract: A broadband adaptively controlled polarization separation network. Two transmitted signals vertically and horizontally polarized are received as elleptically polarized signals. One of the two received elliptically polarized signals is automatically adjusted to make it linear and thereafter automatically adjusted to make it vertical. If the other signal does not have any vertical polarization on it then the two signals are easily separated and nothing else is needed. However, if there is any vertical polarization on the other signal this invention provides for separating the resulting crosstalk between the two signals. This is done automatically by the use of two sets of crosscouplers which couple a single line to the other line to complete the polarization decoupling operation.