Abstract: A rectangular waveguide to circular waveguide coupler and vice versa. The upler includes a first section of circular waveguide spaced by a gap from a reflective-plane conducting wall, the latter having a hole for passage of an electron beam if the coupler is used in a traveling wave tube, and a second section of circular waveguide disposed external to, and coaxial with, at least a portion of the first waveguide section and extending to the wall to provide a conductive boundary surrounding the gap. The region between the first and second waveguide sections forms an input port of the coupler; the first waveguide section forms the output port of the coupler. Electromagnetic waves in a TE.sub.01 coaxial waveguide mode are applied to the input port from a rectangular waveguide supporting the dominant TE.sub.10 mode. The second waveguide section has a cut-off determining dimension r.sub.e proportioned to support both the TE.sub.01 and TE.sub.

Abstract: Microwave integrated circuits are enclosed in metal boxes. As more functions are added to circuits RF moding increases. One method of minimizing RF moding is to place a post in the box. This invention broadens the band of frequencies controlled by the post method by attaching a lossy RF absorbing pellet to the end of the mode suppression post.

Abstract: A rectangular waveguide elbow formed with a truncated beveled corner on its outer edge and formed with a conductive cross bar which extends between the narrow walls of the waveguide and which is positioned midway between the inner corner of the waveguide elbow and the center of the truncated wall and further including an extending electrically conducting cylinder mounted on the interior surface of the truncated wall with its center on the diagonal of the truncated wall. The diameters of the conductive cross member and of the conductive metal cylinder are chosen so as to minimize the reflection factor and thus to reduce the reflection factor over a relatively broad-band.

Abstract: Transmission line apparatus for transmitting TE dominant electromagnetic waves is provided in accordance with the teachings of the present invention. The transmission line apparatus according to the present invention relies upon a transmission waveguide having a uniform cross-section which is substantially larger in dimension than that required for propagation of only the TE dominant electromagnetic wave desired to be transmitted. The transmission waveguide is in fact so large with respect to the transmission frequency for the TE dominant electromagnetic wave selected that a plurality of waves can form and be propagated, however, losses along the waveguide are markedly reduced. The transmission waveguide is provided with guides in the form of structure present in the waveguide which prevents a rotation of the plane of polarization of the TE dominant electromagnetic waves being transmitted.

Abstract: Periodic fins are provided on the lid of a microwave integrated circuit (MIC) package in order to reactively suppress specified bands of frequency and thereby increase the permissible dimensions of the MIC package.

Abstract: A radio frequency power divider/combiner having a pair of conductive plates between which the dominant E-type mode is produced by symmetrical excitation at a central point preferably by means of a coaxial line having its outer conductor attached to the first of these plates, and its inner (center) conductor passing freely therethrough and attaching to the second of these parallel plates in an impedance matching flareout. A plurality of uniformly distributed collectors each in the form of a loop feeding the coaxial branch port provides for low loss. The entire assembly is in the form of a thick disc with radially extended branch ports about its perimeter and a common excitation feed extending normally from the surface of the first plate. Resistors are provided between adjacent portions of the end-on loops for the suppression of circumferential current components corresponding to undesired modes.

Abstract: A waveguide to microstrip transition for transferring guided electromagne signals from dominant mode rectangular waveguide to microstrip line and vice versa. A microstrip printed circuit card is disposed in parallel to the narrow walls of a waveguide. The printed circuit card includes a microstrip stepped transformer section followed by a linear taper crossover section. The linear taper crossover section leads into a microstrip line conductor and ground plane for completing the transition.

Abstract: A waveguide junction circulator which includes means for absorbing spurious modes. A thin, lossy element (15) is provided surrounding a portion of the gyromagnetic member (4) and orthogonal to the electric field of the incident wave. The incident wave is unaffected, but the spurious modes which are produced in the gyromagnetic member and exist as high Q resonances are selectively absorbed. The lossy element is typically a thin film resistor formed on a dielectric film.

Abstract: A mode filter apparatus for preventing unwanted modes in a multi-moded structure utilizing a radial plurality of resonant slots on the bottom of the filter cavity. The top of the filter cavity includes a variable height center section to provide mode selectivity in cooperation with the resonant slots.

Abstract: A ground plane element in a channel has a width slightly less than the channel width, thus forming a ridge mode waveguide. Means such as conducting strips are used to suppress the ridge mode. The strips are preferably corrugated for good contact and to firmly secure them. The suppressing means can prevent bypassing a microwave low pass filter.

Abstract: The invention relates to mode filters for millimetric waves. The mode filter provided includes a circularly sectioned waveguide divided into a number of equal sectorial channels. Dielectric mode perturbing material is provided in all but one of the channels. This material extends in the direction of the H-field so as not to interfere with a wanted mode of a propagated signal but to perturb the current lines of an unwanted TE.sub.On mode so that an -unwanted TE.sub.On mode in the channel containing the dielectric material undergoes a .pi.radian phase shift relative to the TE.sub.On mode in the remaining channel which remaining channel has a conductive sectorial ridge of the same cross section as the sectorial channels and extending in the direction of the H-field the ridge being of such a radius that differential phase shifts produced by the perturbation effect of the mode perturbing material of the wanted mode cut-off frequency are substantially reduced.

Abstract: A waveguide power limiter comprising a ferrite slab provided with one or more cavities containing dielectric inserts. The slab is positioned in a waveguide and the cavities may be graded so that different portions of the slab have different power limiting ranges.

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 device for attenuating electromagnetic cavity interference waves, which occur in the vacuum system of a high-frequency electron tube, in particular a transmitting tube, comprising a wave-guide portion coupled to the cavity of the electron tube, which may or may not form a part of the vacuum system of the electron tube, and which wave-guide portion may have a length corresponding approximately to a quarter wave length of the interference waves, and is provided with a high-ohmic resistive coating, the high resistance of which is transformed by the wave-guide portion into a low resistance with respect to the cavity interference waves which are to be attenuated, in the cavity of the electron tube.

Abstract: The present invention provides a polarization coupler which is capable of coupling or separating dual linear polarized microwave signals having frequencies which extend over extremely wide frequency bands. The present polarization coupler (11) comprises a main waveguide (12) and a side-arm waveguide (13) with a plurality of septa (16) arranged at the junction to reflect energy of a first polarization (E.sub.1) between the main and side-arm waveguide while energy of a second polarization (E.sub.2) passes the junction unaffected.

Abstract: Input and output waveguides are each formed from an inner tubular conductor coaxially disposed within an outer tubular conductor. The proximal ends of the waveguides are coupled through relatively rotatable sleeves of a coupling assembly that maintains the waveguides coaxial with a central axis. The field strength of a wave at the distal end of the input waveguide defines two cycles of a sinusoid about the axis. The inner conductors each carry on their outer surface an equal number of evenly spaced ridges. The ridges in the input waveguide cause the field strength to be invariant at the proximal ends. The ridges in the output waveguide cause the field strength to define the two cycles of the sinusoid at the distal end of the output waveguide.

Abstract: A series connection of n diplexers is used as a multiplexer for separating a hyperfrequency band into n + 1 sub-bands (or vice-versa). Each diplexer comprises a semi-circular inlet coupler followed by a semi-circular high-pass filter and by a semi-circular outlet coupler, the filter at each stage is dimensioned to reflect only the lowest of the sub-bands which it receives from the previous stage. The creation of unwanted parasitic modes in the reflected sub-band is avoided by so choosing the radius of the inlet coupler that the reflected sub-band lies between the frequencies at which the parasitic TE.sub.12 and TE.sub.22 modes occur. This is achieved by use of the relationship ##EQU1## WHERE V IS THE SPEED OF LIGHT, FMAX AND FMIN ARE THE UPPER AND LOWER LIMIT FREQUENCIES OF THE REFLECTED SUB-BAND AND P'.sub.12 and P'.sub.22 are the second zeros of the first and second order Bessel functions characterising the respective semi-circular TE.sub.12 and TE.sub.22 modes.