Abstract: A multiplexer/demultiplexer structure is provided which multiplexes multiple channel signals through a common tee of a tee/manifold mulitplexer arrangement. This multiplexing significantly reduces the number of tees required for a given number of multiplexed channels. Accordingly, mulitplexer/demulitplexer design time is reduced and fabricated multiplexers/demultiplexers are lighter, smaller and less expensive. The tee multiplexing is facilitated with multiple access apertures that are isolated by a septum. The septum forms reduced-height waveguides which define a path length between apertures that is sufficient to significantly reduce higher-order modes and, therefore, apeture interactions.

Abstract: An electromagnetic resonator comprises a waveguide body having a generally tubular side wall and a pair of end wall assemblies. The end wall assembly includes a bowed aluminum plate and an INVAR disk, attached to one another at the periphery thereof. The INVAR disk includes a relatively thick outer annular portion and a relatively thin inner circular portion. The bowed aluminum plate bows in response to increased temperature, thereby counteracting expansion of the waveguide body.

Abstract: A microwave filter includes two resonant cylindrical cavities aligned in parallel along their longitudinal axes, with the cavities offset by one half the cavities' resonant wavelength with respect to one another. Signals to be filtered are coupled into a first, input, cavity through an input coupling and between the input cavity and a second, output, cavity through bridge and mainline couplings formed in a common cavity wall.

Abstract: A high Q microwave filter is disclosed. Coupling bar structures are included in a cylindrical resonator, extending substantially the entire length of the resonator for coupling orthogonal modes. The coupling bars have a lower profile than conventional tuning screws. The symmetry of the filter structure is improved over the prior art coupling devices which relied entirely on tuning screws for coupling E fields of one mode to the other mode. The coupling bar structure has a lower profile penetrating less into the supported E fields while obtaining the desired coupling. Increased bandwidth may be obtained at improved symmetries over the prior art devices. Fine tuning may be provided by inserting tuning screws into the cylindrical cavity. The tuning screws require less penetration as substantially most of the coupling occurs by virtue of the coupling bars.