Abstract: A linear microwave attenuator has an absorbing element which is selectively shaped to provide reduced capacitive coupling and increased attenuation by segmenting the absorber into at least two members. The selective shaping reduces both the surface area and mass of the absorber while maximizing the attenuation of possible from the absorber. In this way, reduced size, linear performance, and increased attenuation over those of the prior art are provided by the present invention.

Abstract: A wideband balanced diplexer splits an incoming wideband microwave frequency signal into separate upper and lower frequency outputs and possesses a sharp band cut-off to increase effective bandwidth. The diplexer includes a pair of waveguide assemblies for separating the upper frequency band from the incoming signal. Each waveguide assembly includes a tuneable, ridged waveguide phase shifter for shifting the phase of the lower frequency band, a reference waveguide for inserting a delay onto the upper frequency signal in order to compensate for the effects of the phase shifter in the other waveguide assembly, and a high pass filter. The high pass filter includes a ridged waveguide having tapered ends of a shape comprising an exponential function raised to a cosine squared power to increase the bandwidth of the upper frequencies and to provide a sharper frequency cut-off.

Abstract: An iris is located in a common wall separating two microwave enclosures such as waveguides and cavities for coupling electromagnetic power between the two enclosures. The iris is formed of an aperture elongated in one direction to define a longitudinal axis of the aperture with opposed first and second sides parallel to the axis. Portions of the common wall at peripheral regions of the aperture are extended from the first and second sides towards the iris and perpendicularly thereto to form teeth, there being an array of teeth extending from the first side and an array of teeth extending from the second side. The teeth are readily polarized as magnetic dipoles by surface currents induced in the wall by electromagnetic waves for increased coefficient of coupling of electromagnetic field components through the iris.

Abstract: The present invention relates to an E-plane type wideband composite filter comprising a conductive screening body (11, 12) having an elongate cavity (14) therein with a blade cut into a ladder shape disposed longitudinally therein. Said body comprises two portions held against each other on either side of a separation plane along which said ladder (15) is disposed, with two irises (16, 17) being disposed transversely at the inlet and at the outlet of said cavity (14), each closing off a portion thereof.

Abstract: A flexible low-loss dielectric waveguide is made from a flexible low-dielectric constant hollow cylinder filled with high-dielectric constant powder. Alternatively, a rigid or semi-rigid waveguide comprises a groove formed in a low-dielectric constant substrate filled with high-dielectric constant powder.

Abstract: A method of fabricating hollow square inner conductors having precise outer dimensions is disclosed. A first "u" shaped slot (10) is machined in a base plate (12) and a cover plate (16) is then brazed to the sloted surface (18). The cover plate (16) is machined to provide a first wall (20) of desired thickness. Second and third slots (22, 24) are machined in the base plate (12) parallel to the first slot (10) on opposite sides thereof to provide second and third walls (26, 28) of the hollow conductor (38). A sacrificial metal (30) having a melting point below that of the base plate metal is cast into the second and third slots (22, 24). A fourth wall (36) is formed by machining material from the base plate face (32) opposite the slotted surface (18). The sacrificial metal (30) is then removed to provide the hollow inner conductor (38) having precise outer dimensions (A, B).

Abstract: An apparatus 10 with gears (22a, 22b, 22c, 25) for adjusting the position of a plate (13) in a cavity (12) and a rack (51) and gear (53) for moving a probe (15) into and out of the cavity is described. The apparatus includes knobs (34, 55) for controlling the movement of the plate and probe. Micrometers (37, 52) measure the precise position of the plate and probe in the cavity. The apparatus allows very precise tuning for selection of a mode of radiofrequency wave in the cavity and fine tuning within the mode.

Abstract: Universal waveguide joint, provided with at least two waveguide segments (1-7) slidable over each other, whereby one end of at least one of the waveguide segments (1-7) has a convex surface and the end of another respective waveguide segment, slidable over said convex surface, a concave surface.

Abstract: A delay line is provided for effecting a desired delay in the transmission of electromagnetic waves in the microwave and millimeter range of the spectrum. The line comprises a length L of a dielectric waveguide for transmission of electromagnetic waves comprising a core of polytetrafluoroethylene having one or more layers of polytetrafluoroethylene overwrapped around the core, wherein T=KL/c, in which T is the total time delay , c is the velocity of light in free space and K is the delay constant of the dielectric waveguide. Preferably, the delay line is overwrapped around a mandrel.

Abstract: A filter system is composed of two identical filters coupled between an input waveguide and an output waveguide to provide a 4-port directional filter characteristic operable with quasi-elliptic linear modes of electromagnetic propagation within each of the filters. Each of the filters may be constructed of a plurality of cavities arranged serially, one behind the other, with one of the cavities in each of the filters being employed for coupling electromagnetic power between the two waveguides. The coupling is accomplished by use of a transverse slot and a longitudinal slot in each of the waveguides, the slots extending through sidewalls of the waveguides into walls of the cavity in each of the filters for symmetric and antisymmetric coupling, respectively, of longitudinal and transverse components of a transverse electric wave in each of the waveguides.

Abstract: A probe coupled waveguide multiplexer is provided including a first waveguide which serves as a multiplexing manifold; a second waveguide, having a cavity, typically a filter, which is probe coupled to the first waveguide; and a third waveguide which has a cavity and is probe coupled to the first waveguide such that the probe of said third waveguide is diametrically opposed to the probe of said second waveguide and the second and third waveguides are mounted in the same transverse plane in co-planar relation. The probe coupling method and apparatus disclosed herein allows the waveguide filters to be mounted on the manifold in a close physical relation thereby minimizing the length of the manifold and associated costs.

Abstract: A microwave filter composed of a plurality of cylindrical cavity resonators each having a side wall extending parallel to the direction of wave propagation in the resonator, wherein the cavity resonators are disposed with their side walls in contact with one another in a compact cylinder pack arrangement so that the side wall of each cavity resonator is in contact with the side wall of the maximum number of other mutually adjacent resonators, and coupling structures connecting resonators whose side walls are in contact, via the contacting side walls, for coupling electromagnetic energy between the resonators.

Abstract: A microwave phase shifter comprise a dielectric waveguide having a flat side and a moving conductor plane member substantially parallel to the waveguide side. Piezoelectric means are provided to move the plane member with respect to the waveguide side between a portion relatively remote from the waveguide side and an other position substantially in contact with the waveguide side. The piezoelectric means consists preferably of a stack of piezoelectric members supplied by a variable d.c. power source. Owing to the piezoelectric means for moving the conductor plane member, a variable phase shift is continuously adjusted. Such a phase shifter can be as an antenna network when the dielectric waveguide contains groups of radiator perturbations, such as conductor strips, respectively controlled by one or several piezoelectric means carrying conductor plates facing waveguide portions including the perturbations groups.

Abstract: A hanger for attaching a length of waveguide of elliptical cross-section to a crossbar on an antenna tower. The hanger comprises a resiliently yieldable and generally U-shaped clip adapted to be slipped into straddling relation with the waveguide and simultaneously inserted into a hole in the crossbar with a snap fit.

Abstract: A microwave absorber with a microwave-absorbing material, a protective hong surrounding this, and a waveguide leading into the protective housing, through which waveguide the microwaves to be absorbed can be conducted to the absorbing material, the microwave-absorbing material forming a solid body with a hollow, on one side of which the waveguide opens, a termination element being arranged on the side of the hollow opposite to the waveguide, and the housing being provided with an inlet and an outlet for a cooling fluid.

Abstract: An improved serpentine feed and method of making same. The invention includes a block of conductive material having a primary microwave waveguide channel and at least one secondary channel. Each secondary channel has at least one broadwall common to the primary channel. A high performance coupler is provided in the common broadwall by which microwave energy communicates from the primary channel to the secondary channel.

Abstract: A microwave calorimeter for very high power, with a housing, which surrou a feed chamber, into which a waveguide runs for feeding the microwaves, and an absorber-chamber which is separated from the feed chamber by a dielectric wall and contains a microwave-absorbing fluid, the fluid consisting at least in part of a compound whose capacity for the absorption of microwaves is less than that of water.

Abstract: A launcher of cross-polarized electromagnetic radiation is provided with increased bandwidth by inserting a set of axially directed ridges on the interior surfaces of waveguide walls of the launcher for concentrating electric fields of radiations of the different polarizations. A first radiation radiated by a probe in a back section of the launcher waveguide propagates forward into a front section of the launcher waveguide. A second radiation is radiated into the front section by a probe therein, there being a vane disposed in the front section for inhibiting the propagation of the second radiation into the back section. The front section is flared to provide a larger exit aperture at a front end of the front section. A second and a fourth of the ridges are tapered towards the back section to permit a smooth transition in the propagation of the first radiation into the front section.

Abstract: A microwave power sensor utilizing a semiconductor power absorption element which is mounted on a fin-line structure within a waveguide channel. In order to check calibration of the sensor, a coaxial line is used to feed a relatively low frequency reference signal to the power sensor. The power element is positioned between the input port of the waveguide and a coaxial line input port at which the reference signal is applied. The use of a precise and accurate reference signal enables the power sensor to be used for microwave measurements.

Abstract: A fin-line resonance isolator has layers of hexagonal ferrite material that are stacked relative to one another so that the overall length of the isolator remains substantially constant as the number of layers of ferrite material increases. The isolator has substrate materials that are arranged so that the plane of circular polarization is shifted to a center of the isolator. Isolators of the present invention are capable of producing improved responses over prior art isolators while reducing insertion loss and achieving a weight and volume saving.

Abstract: A resonant cavity waveguide coupler for ICRH of a magnetically confined plasma. The coupler consists of a series of inter-leaved metallic vanes disposed withn an enclosure analogous to a very wide, simple rectangular waveguide that has been "folded" several times. At the mouth of the coupler, a polarizing plate is provided which has coupling apertures aligned with selected folds of the waveguide through which rf waves are launched with magnetic fields of the waves aligned in parallel with the magnetic fields confining the plasma being heated to provide coupling to the fast magnetosonic wave within the plasma in the frequency usage of from about 50-200 mHz. A shorting plate terminates the back of the cavity at a distance approximately equal to one-half the guide wavelength from the mouth of the coupler to ensure that the electric field of the waves launched through the polarizing plate apertures are small while the magnetic field is near a maximum.

Abstract: A waveguide filter is provided which comprises a plurality of waveguide resonators arranged in series in the longitudinal direction of the filter with each contacting tightly with adjacent ones, each of the waveguide resonators being composed of a rectangular dielectric having a length and a permittivity complying with the center frequency of a bandpass filter, on the periphery of which a metal film is provided except on the portions of induction windows of its two sides mutually opposed in the longitudinal direction.

Abstract: A monopulse comparator is formed by milling grooves in opposed surfaces of aluminum circular blocks. The milled grooves define a number of waveguides, ports and hybrid junctions. A, B, C and D ports are coupled by respective waveguides to respective side branches in first and second hybrid rings. The series branches of these hybrid rings are coupled by respective waveguides to parallel and series branches respectively of a third ring hybrid ring. One side branch of this hybrid ring is coupled to an azimuth differential port by one of the waveguides. The other side branch is coupled to a termination by a waveguide. The parallel branches of the first and second hybrid rings are coupled by respective waveguides to respective side branches of a fourth hybrid ring. The parallel branch of this hybrid ring is coupled by a waveguide to the elevation differential port. The series branch of this hybrid ring is coupled by a waveguide to the sum port.

Abstract: The waveguide includes an input section and a short circuit section which each have a hollow interior of like size and shape enclosed by a surrounding wall. In arrangement, the input and short circuit section are in spaced alignment, and the stripline is interposed in the gap between the two sections. The stripline includes ground planes on either side thereof, and apertures are cut into the ground planes of the same size and shape as the hollow interiors, and, in arrangement, the apertures are in alignment with these hollow interiors. A wall of pins is disposed between the two sections whereby to simulate the continuation of the waveguide walls. The position of the transition may be arbitrarily chosen to suit the design of the stripline circuit.

Abstract: A pivotal joint for waveguides provides a low-loss interface between two rigid waveguides at which relative movement can occur. The pivotal joint has two waveguide sections which are terminated in conical surfaces containing concentric chokes to minimize RF energy leakage. A universal gimbal is utilized to position the joints so that the pivotal motion occurs about the apices of the chokes. The advantages of this RF joint include zero bending torque, absence of a fatigue failure mode, low insertion loss and a good impedance match at all angles of operation and over large bandwidths.

Abstract: A small antenna including a dielectric plate, upper and lower conductive plates provided on upper and lower faces of the dielectric plate, respectively, a plurality of conductive reactance posts for connecting, at first positions of the dielectric plate, the upper and lower conductive plates to each other, and a feed point provided at a second position of the dielectric plate such that first and second plane-parallel plate transmission lines separated from each other by the reactance posts are formed by the upper and lower conductive plates.

Abstract: Dessicant vessel allows air to flow through desiccant from a temperature related pumping phenomena prior to entry into waveguide to guard against attenuation of microwave signal.

Abstract: A transmission line comprising a multi-layer dielectric slab structure including: a dielectric substrate layer (30) having a thickness d.sub.s and permittivity .epsilon..sub.s ; a conductive ground plane (31) on the bottom surface of the dielectric substrate layer (30); a dielectric guiding layer (32) having a thickness h and permittivity .epsilon..sub.g, where .epsilon..sub.g >.epsilon..sub.s, attached to the top surface of dielectric substrate layer (30); at least one elongated and relatively narrow dielectric loading strip layer (33) having a width W, thickness d.sub.1, and permittivity .epsilon..sub.1, where .epsilon..sub.g >.epsilon..sub.1, attached to the top surface of the dielectric guiding layer (32); and a conductive coating (34) on the top surface of the dielectric loading strip layer (32). Such a structure permits single mode propagation over a relatively wide band.

Abstract: A phase compensated waveguide hybrid coupler is formed with a pair of waveguides of rectangular cross section and sharing a common short wall. An aperture in the short wall provides for the coupling of electromagnetic energy between a first of the waveguides and a second of the waveguides. Such coupling introduces a 90.degree. phase shift. An input terminal is located at an end of the first waveguide. Phase compensation is introduced by a set of capacitive irises located in the first waveguide and by a set of inductive irises located in the second waveguide. The capacitive and inductive irises are located on a side of said coupling aperture away from said input terminal.

Abstract: For high power application of overmoded waveguide, air cooling is provided by applying air flow to the overmoded waveguide either directly or indirectly, through an air inlet which does not significantly disturb the internal electromagnetic fields.

Abstract: An adjustable waveguide short circuit using a thin partition or rectangular pin parallel to the E-field in the waveguide and movable along longitudinal slots centrally located on the two broad walls of the waveguide.

Abstract: A waveguide hybrid coupler is formed with a pair of waveguides of rectangular cross section and sharing a common sidewall. An aperture in the sidewall provides for the coupling of electromagnetic energy between a first of the waveguides and a second of the waveguides. An input terminal is located at an end of the first waveguide. A pair of stepped, multi-tiered abutments are disposed on the outer sidewalls of the waveguides opposite the coupling aperture. The dimensions of the abutment steps are selected to stagger-tune the frequency response of the coupler to achieve wideband operation.

Abstract: A waveguide lowpass filter has successive groups of three separate ridges spaced longitudinally in said filter. A center ridge of each filter has a larger cross-sectional area than two side ridges which are the same size. All ridges are parallel to one another in a longitudinal direction. The groups are associated with shunt capacitances and the spaces between adjacent groups are associated with series inductances in an evanescent mode. In operation, the filter is capable of supporting a TE.sub.10 mode in the passband and three modes, TE.sub.10, TE.sub.20 and TE.sub.30 in the stopband. The filter has a relatively high power handling capability as compared to previous evanescent mode lowpass harmonic filters.

Abstract: A phase shifter for microwave electromagnetic energy propagating through a waveguide has a composite structure of a series of capacitive phase shifting posts positioned within the waveguide diametrically across from a symmetrically tapered ridge. The series of posts introduce a nominal value of phase shift with an incremental value which increases with increasing frequency of the electromagnetic energy. The tapered ridge introduces a nominal value of phase shift plus an incremental value which decreases with increasing frequency of the electromagnetic energy. The rates of increase and decrease of the incremental values of phase shift cancel so as to provide a resultant phase shift which is substantially invariant with frequency.

Abstract: A spring hanger system for supporting a UHF circular waveguide from a transmission tower and including a plurality of vertically spaced spring hangers, each adapted to engage an adjacent section in the vertical run of waveguide in the tower. Each hanger includes a glide ring fixed to the tower for restraining the waveguide from movement in any direction except vertical; a clamping ring spaced axially below the glide ring which is adapted to grip the outer periphery of the waveguide snugly without distorting same, whereby the waveguide is stiffened against deformation by lateral forces in the region of the glide ring; and a spring mechanism connecting the glide ring and the clamping ring with a substantially constant force which allows the waveguide to move in response to differential expansion with respect to the tower.

Abstract: A waveguide-to-coaxial converter has a dielectric element attached to a ridge provided inside a waveguide. A coaxial line for a converted wave output which is secured to an output side of the ridge is DC insulated by the dielectric element from the waveguide.

Abstract: A rotary microwave switch is composed of a housing having a side wall, a housing interior cavity, and a plurality of waveguide ports distributed around the side wall. A rotor having at least one rotor cavity is mounted within the housing interior cavity and an electrically conductive plate is fastened to the rotor and has at least one gap constituting a waveguide section. The gap is in communication with the housing interior cavity and the rotor cavity. The rotor is mounted for rotation, relative to the housing, into at least one operative position for causing the waveguide section to establish a signal conducting connection between two of the ports.

Abstract: A miniature microwave guide is provided in a substrate made of successive superimposed layers of conductive and/or dielectric materials. Probes are provided at the extreme ends of the guide for injecting and extracting signals.

Abstract: An articulated linkage is disclosed for supporting waveguide and electrical cabling through a predetermined range of movement. The linkage comprises a plurality of elongated rigid sections, joined by articulated joint sections. The joints comprise at least two short links which are pivotably connected to each other and the adjacent rigid sections. Travel limit pins are provided to limit the pivoting motion of the joint links relative to each other and the rigid sections. The lines of waveguide comprise respective sections of flexible waveguide passing through the flexible joints of the linkage and are connected to elongated sections of rigid waveguide which are supported by the rigid sections of the linkage. The travel limits on joint movement are selected to limit the angular excursions to protect the flexible waveguide from undue stresses during movement of the linkage.

Abstract: A waveguide lowpass filter operates in at least two evanescent modes. The filter has successive ridges with a space between said ridges. The ridges are associated with parallel capacitance and a space between them is associated with series inductance in the TE.sub.10 mode. Each ridge is top-loaded so that series capacitance can occur in a TM.sub.11 mode in parallel to said series inductance. The filters of the present invention can be made smaller than previous evanescent lowpass filters and can achieve improved results.

Abstract: A hollow waveguide element for waveguide systems for microwaves has a wall consisting at least partially of a sintered material to permit gas exchange between the interior and outer surroundings of the waveguide element. With highly loaded gas-filled waveguides this makes it possible to easily carry away discharge products caused by arcing in the interior of the waveguide.

Abstract: An electric field probe is disclosed as having an arcual shaped transmission line which is mounted over a substrate having a corresponding arcual shaped transmission line deposited thereon. The two arcual shaped transmission members overlap such that the electric field energy sampled by the probe may be communicated to a monitoring circuit or the like. Rotating the probe, varies the portion of the arcual shaped members that overlap thereby adjusting the physical and electrical length of the transmission line. Accordingly, the phase of the field energy will shift as viewed from the output port.

Abstract: A waveguide or waveguide phase shifter is terminated with a short circuit provided by a rigid conductive block which is sized to be a close tolerance fit within the waveguide. The block has grooves in its faces adjacent to the waveguide walls. The walls of the waveguide are deformed to project into these grooves to permanently secure the waveguide to the block.

Abstract: The microwave power head or modular heat applicating unit comprising a resonator, a waveguide, a source of microwave energy and a water load device. The resonator is divided into two chambers by a center wall member. A microwave energy receiving antenna means is operatively connected to the center wall for coupling microwave energy into the resonator. A microwave energy transmitting antenna spaced from said receiving antenna is operatively connected to the center wall for transmitting microwave energy from the resonator to a water load. In this manner, the resonator provides a dual function.

Abstract: A heat applicating device having a resonator divided into a plurality of chambers by one or more energy radiating wall like members. The energy radiating wall member is coupled to a microwave energy source at a point on one edge thereof whereby a magnetic field is generated along the opposite (upper) edge of said wall member. An elongate slot is provided in the resonator generally above the upper energy radiating edge portion of the wall member. The ends of the wall member are sloped to provide a gradual termination of the electrical field.

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 microwave power head or modular heat applicating unit comprising a resonator, a waveguide, a source of microwave energy and a water load device. The constituent units or modular components of the power head are arranged in a sandwich like manner to form a readily repairable/replaceable microwave heat applicating device.

Abstract: A reflection phase shifter connectable to a waveguide for shifting the phase of a high frequency signal received from the waveguide. The phase shifter includes a waveguide section having two pairs of opposite side walls and an end wall forming a short-circuit. The side walls define a cavity and an opening opposite to the end wall for communication with the waveguide. The waveguide section has a broad dimension between one pair of opposite side walls corresponding to the width dimension of the waveguide and a narrow dimension between the other pair of opposite side walls which is smaller than the height dimension of the waveguide. A switchable semiconductor arrangement, including a switching semiconductor element and a housing for accommodating the switching semiconductor element, is adjustably mounted in a side wall of the waveguide section and penetrates into the said cavity with a controllable penetration depth for tuning said waveguide section for a desired phase angle shift.

Abstract: A low-loss bandpass microwave filter is disclosed which enables filter size reduction in the frequency range of 1-5 GHz. The filter includes a main ceramic body member which is notched or drilled and coated over all exposed surfaces except for opposite end portions. Coupling terminals are attached to the opposite end portions to provide microwave input and output coupling to the filter.

Abstract: Absolute electrical parameter values using reflected microwaves are achieved through measurement of a sample that completely fills the cross section of the waveguide. A test sample holder for a wafer shaped sample employs a choke flange type plate and a backing plate for the wafer. Semiconductor sheet resistivity and mobility values are measured.