Abstract: A DC bias device for radio-frequency transmission systems of high power and low intermodulation connected between an originating station and a receiving station for an RF signal fed along a transmission line. Direct current is supplied from a source to the transmission line along a branch joined to the transmission line at a junction formed between the originating station and the receiving station. An open-circuit stub is formed along the transmission line between the transmitting station and the junction. A short-circuit stub is formed along the DC-supply branch between the source and the junction to the transmission line. The impedance (Zop) of the open-circuit stub, and the distance of the free heads of the near ends of the two stubs preferably is as low as possible.

Abstract: A power microwave band-pass filter having very high quality factor (i.e., very low insertion loss) and selectivity, includes a cover and a body with dielectric resonator containing cavities. Non-adjacent cavities are cross-coupled by trapezoidal shaped bridging elements, at least one of which is associated with the cover and at least one of which is associated with the filter body. Each bridging element is penetrated in a slit of an electrically insulating holder placed in a knot of two non-adjacent cavities. The bridge element associated with the cover is grounded and acts inductively while the bridge element associated with the filter body is not grounded and acts capacitively.

Abstract: A circuit component for separating and/or combining two pairs of high-frequency signal waves lying in different frequency bands, the waves of each pair having the same frequency but mutually orthogonal planes of polarization, comprises two mutually identical and aligned 3dB couplers bracketing a filtering assembly between them. Each 3dB coupler has a central guide of square cross-section surrounded by four collateral guides, each connected with the central guide by a coupling guide letting only the waves polarized in one plane--regardless of frequency--pass therebetween. The filtering assembly has sets of baffles in line with the central and collateral guides of both couplers, these baffles defining slots giving passage to only the waves of one of the two bands while reflecting the others.

Abstract: A circuit component for use with signals of superhigh frequency, on the order of 10 GHz or more, has a waveguide structure with four conductive walls defining a channel of rectangular cross-section, the channel bottom being overlain by a dielectric layer supporting at least one microstrip of copper or the like closely spaced from one of the lateral walls. The supporting layer preferably consists of a polymeric material of relatively low dielectric constant, e.g. between 2 and 3. The width and height of the channel are less than half the free-space wavelength of the highest-frequency signal to be transmitted; the circuit is tuned by metallic screws which are threaded into the adjoining wall and partly overlie the microstrip at a low level, the axes of adjacent screws being separated by less than an eighth of that wavelength.

Abstract: A conductive body with a cylindrical cavity, designed to resonate at a certain operating frequency in the TE.sub.01 mode, has an input opening at one end and a conductive insert at the opposite end which alters the effective axial length for parasitic waves propagated in the TM.sub.11 mode. The insert may have the form of a smaller cylinder with a closed end beyond that of the main cavity, increasing the effective length, or of a set of radial vanes reducing the effective length. The insert, in either case, may be axially shiftable to tune the cavity to different resonant frequencies.

Abstract: A station for the transmission and reception of electromagnetic waves (e.g. from a communication satellite in stationary earth orbit), operating in a multichannel band with two conjugate polarizations, includes a regenerative distortion compensator in a receiving waveguide branch and a predistorter in a transmitting waveguide branch, both controlled by a processor responsive to output signals from a subsequent i-f stage in which a distortion monitor measures cross-talk between the two polarizations on the basis of two central beacons extracted from the incoming message band.