Abstract: A plasma processing apparatus includes: a coaxial tube that extends in a vertical direction and forms a portion of a radio frequency waveguide; a substrate support configured to support a substrate; an electrode including a gas flow path connected to a gas ejection port opened toward a space above the substrate support, wherein the electrode is provided above the substrate support and an inner conductor of the coaxial tube is connected to a center of the electrode; an enlarged diameter portion forming a part of the radio frequency waveguide together with the electrode and connected to an outer conductor of the coaxial tube; and dielectric tubes formed of a dielectric material, wherein each of the dielectric tubes is connected to the electrode and penetrates a space between the electrode and the enlarged diameter portion to supply a gas to the electrode, wherein the dielectric tubes is scatteredly provided.

Abstract: This document describes apparatuses, methods, and systems for a hybrid horn waveguide antenna. The hybrid horn waveguide antenna includes a waveguide, described in two sections, and an antenna section having both flaring features and step features. The first waveguide section is electrically coupled to a transmitter/receiver (e.g., transceiver) and defines an energy path along an x-axis. The second waveguide section transitions the energy path to travel along a z-axis. The antenna section has a first aperture that is coupled to the second waveguide section and includes flaring wall features in one plane (e.g., the E-plane) and step features in a second plane (e.g., the H-plane). The waveguide may further include an iris between the first waveguide section and the second waveguide section. Further, the hybrid horn waveguide antenna section may be formed from an upper structure and a lower structure manufactured via injection molding and then mated.

Abstract: Provided are a phase shifter, a preparation method thereof, and an antenna. The phase shifter includes at least one phase shifting unit, and the phase shifting unit includes a microstrip line, a photo-dielectric layer, a ground electrode, and at least one light guiding structure; the microstrip line is located on a side of the photo-dielectric layer, and the ground electrode is located on a side of the photo-dielectric layer facing away from the microstrip line; the light-guiding structure at least partially overlaps the photo-dielectric layer, and the light-guiding structure is configured to guide light into the photo-dielectric layer.

Abstract: An antenna comprises a main reflector, a waveguide, wherein at least part of the waveguide protrudes towards a region external to the antenna, wherein the antenna is operative to transmit electromagnetic radiations between the waveguide and the main reflector, a mechanism which enables displacement of at least part of the waveguide with respect to the main reflector, and an actuator operative to displace the at least part of the waveguide.

Abstract: Radio frequency (RF) polarizer feeds and associated waveguide structures having twist features are discussed herein. In one example, a first waveguide segment spans a longitudinal axis between a feed port and a twist port and includes two stacked rounded rectangular elements skewed in minor axis alignment with respect to each other and having major axes perpendicular to the longitudinal axis. A second waveguide segment spans the longitudinal axis between the twist port and a polarizer port and is coupled to the first waveguide segment at the twist port. The second waveguide segment includes first ridge elements that span longitudinally from the twist port on first opposing walls of the second waveguide segment, and second ridge elements that span longitudinally from the twist port on second opposing walls of the second waveguide segment.

Abstract: A communication system for communication between at least one vehicle guided along a predefined movement path and a stationary station using a slotted waveguide which extends parallel to the movement path of the vehicle and into which at least one antenna connected to a transceiver unit of the stationary station and at least one antenna of the vehicle project. The antenna of the vehicle is moved in the longitudinal direction of the slotted waveguide with movement of the vehicle. The slotted waveguide includes at least two sections separated from one another by a respective gap. At least one antenna projecting into the respective section is provided for each section of the slotted waveguide. Two neighboring antennas projecting into different sections of the slotted waveguide are coupled via a coupling device both to a common transceiver unit of the stationary station and to one another.

Abstract: Antenna arrays comprising planar combiner networks. An apparatus includes a first antenna component comprising a first multiplexer and a second antenna component comprising a second multiplexer. The apparatus is such that the first antenna component is located next to the second antenna component within an antenna array and the apparatus is disposed within a lattice spacing of the antenna array.

Abstract: Disclosed is a high frequency module for producing or processing radar signals for use in radar-based fill-level measuring devices. The high frequency module includes: a semiconductor component to produce or to process electrical, high frequency signals; a dielectric coupling element contacted with the semiconductor component to couple the high frequency signals as radar signals into a dielectric waveguide or in order to couple radar signals from the waveguide as electrical, high frequency signals into the semiconductor component. The coupling element and the waveguide form a plug contact. In the case of appropriate design of the plug contact there results upon plug-in a self-centering, so that need for a complex adjustment during manufacturing is absent. Since radar frequencies of above 100 GHz can be produced by the semiconductor component, corresponding fill level measuring devices are characterized by a high measuring resolution and compact structures.

Abstract: A printed circuit board is provided, comprising a horizontally extending dielectric substrate and a substrate integrated waveguide (SIW) having at least one ridge. The SIW comprises two horizontally disposed conductive ground planes spaced by a vertical distance, and two vertically disposed conductive fences spanning therebetween. The fences extend in a first horizontal direction, and are spaced from one another in a second horizontal direction, perpendicular to the first horizontal direction. At least one of the fences comprises a plurality of horizontally disposed conductive strips vertically spaced from one another and extending in the first horizontal direction. At least some of the conductive strips are ridge-strips constituting the ridge and extending in the second horizontal direction toward the other of the fences.

Abstract: An electrically isolating gasket is disclosed wherein a coating layer is disposed on at least one conductive surface, and in some embodiments, on all surfaces or at least all of the conductive surfaces. The electrically isolating gasket includes a core gasket component, a ring seal component, and a non-conductive inner seal component. The coating layer can be, for example, polyimide, polyamide, ceramic, and aluminum oxide.

Abstract: A semiconductor device package includes a substrate and a conductive lid. The conductive lid is disposed within the substrate. The conductive lid defines a waveguide having a cavity. The waveguide is configured to transmit a signal from a first electronic component to a second electronic component through the cavity.

Abstract: Embodiments herein describe a capillary containing a eutectic conductive liquid (e.g., EGaIn) and an electrolyte (e.g., NaOH) that is integrated into a printed circuit board (PCB). In one embodiment, the PCB includes a capillary, a negative electrode, a positive electrode, a plurality of insulation layers, and a conductive layer. The capillary extends through the PCB. The capillary includes a side surface forming an annular cylinder. A eutectic conductive liquid and an electrolyte are disposed within an aperture formed by the side surface. An electrode extends through the side surface and contacts at least the eutectic conductive liquid or the electrolyte. The negative electrode is disposed at a first end of the capillary. The positive electrode is disposed at a second end of the capillary. The conductive layer is disposed between two of the plurality of insulation layers. The electrode forms an electrical connection with the conductive layer.

Abstract: A system including a polarized radio frequency (RF) scanning reference source and one or more cavity sensor receivers. The system uses a sensor processor to apply Fourier integration to extract a fundamental frequency and, at least, a fundamental frequency and two predetermined harmonics from the received output of the one or more cavity sensor receivers in determining a reference time of the reference clock.

Abstract: A experimental matching network optimization method for two-stage power amplifiers combines existing technologies such as: Impedance tuners for load pull measurements, computers for RF network synthesis and analysis and numerical optimization algorithms, to create a method for in-situ experimentally verifying and optimizing the effect of matching network designs on overall amplifier performance before their manufacturing. The method eliminates guesswork in amplifier design, especially with regards to the interstage matching network of two-stage RF amplifiers. When properly implemented, the method revolutionizes MMIC amplifier design, by augmenting design confidence and bypassing costly hardware iterations.

Abstract: A radar-based fill-level measuring device, comprises the following parts: a semiconductor component for producing electrical high-frequency signals or for determining the fill-level value from the received high-frequency signals; a dielectric waveguide placed in contact with the semiconductor component to couple the high-frequency signals as radar signals into an antenna and/or to couple received radar signals from the antenna as electrical signals into the semiconductor component; a potting encapsulation, which encapsulates at least the waveguide radially such that a defined cavity is formed between the waveguide and the potting encapsulation.

Abstract: A multidirectional runner assembly for positioning a carrier pipe within a surrounding casing pipe. Each multidirectional runner assembly has at least one ball transfer assembly at least partially protruding from the runner assembly, in order to contact an inner surface of a surrounding casing pipe. The ball transfer assemblies reduce static and/or kinetic friction forces during installation of a carrier pipe within the central bore of a casing pipe, permit multidirectional orientation of the runners within the casing pipe, and provide greater load support.

Abstract: Load pull measurement arrangement having an active tuner with a signal generator providing a signal at a first frequency to a vector modulator. The vector modulator has an input for receiving control signals and is arranged to provide an injection signal at the first frequency based on the control signals. The active tuner further has a frequency multiplier receiving the injection signal and outputting a multiplied injection signal having a second frequency, the second frequency being an integer multiple of the first frequency. Furthermore, a millimeter wave extender has a frequency multiplier in the signal injection path connected to the device under test during operation.

Abstract: The disclosure relates to an electrical component, for example, a surface-mount resonator, including a distributed-element circuit disposed on a dielectric base and separated from an electromagnetic field modification member by a gaseous gap, wherein a frequency characteristic of the electrical component can be tuned by positioning the electromagnetic field modification member relative to the distributed-element circuit using an actuator.

Abstract: A system of a machine includes a waveguide system and a radio frequency transceiver/detector coupled to the waveguide system and configured to emit a calibration signal in the waveguide system to establish a reference baseline between the radio frequency transceiver/detector and a calibration plane associated with an aperture of the waveguide system, emit a measurement signal in the waveguide system to transmit a radio frequency signal from the radio frequency transceiver/detector out of the aperture of the waveguide system, and detect a reflection of the measurement signal at the radio frequency transceiver/detector based on an interaction between the measurement signal and a component of the machine. A measurement result of the reflection of the measurement signal can be adjusted with respect to a reflection of the calibration signal.

Abstract: A W-band E-plane waveguide bandpass filter includes a rectangular waveguide configured to feed a W-band signal, and a dielectric substrate. The dielectric substrate is inserted into the center of the waveguide. The dielectric substrate is provided with a spoof surface plasmon polariton (SSPP) array configured to transmit a TM-mode surface wave to achieve the bandpass filtering response.

Abstract: A ridge gap waveguide millimeter-wave crossover bridge structure device includes: an upper planar metal plate and a bottom planar metal plate arranged in parallel; a supporting structure fixedly arranged between the two planar metal plates; a ridge waveguide fixed on the upper surface of the bottom planar metal plate, with an air gap between the upper planar metal plate and the ridge waveguide; and a plurality of metal pins fixed on the upper surface of the bottom planar metal plate and evenly arranged around the ridge waveguide. The ridge waveguide includes two transmission lines arranged crosswise and four impedance transformation structures respectively connected to the ends of the two transmission lines. The distal end of each of the impedance transformation structures away from the connected transmission line is used to connect with external test equipment to be accommodated in four input ports in the bottom planar metal plate.

Abstract: An electromagnetic waveguide including conductive material on upper lower, and side surfaces of a dielectric is disclosed. A conductive excitation member is electrically coupled to the conductive material on the upper surface of the dielectric and extends to the lower surface of the dielectric at or near an end surface of the dielectric. The conductive excitation member includes a host interface flange separated and electrically isolated from the conductive material on the lower surface of the dielectric. The conductive material on the lower surface of the dielectric can be a ground plane and the waveguide can be a surface-mountable component.

Abstract: An asymmetric, broadband, compact and low-PIM orthomode transducer comprised of two parts is presented. Mating of the two parts results in the formation of a choke flange as well as a critical impedance step which suppresses unwanted modes and enables broadband matching of the junction between the two parts. Furthermore, a cruciform-quatrefoil waveguide type is utilized that transitions to an aperture. This waveguide configuration can lead to a lower overall part length, an improved reflection, and reduced manufacturing costs.

Abstract: The disclosed radio frequency (RF) bandpass filter may include an RF transmission medium that defines (1) a plurality of cavities aligned parallel to each other along a major axis, where (a) each cavity includes planar surfaces that define (i) a first dimension aligned with the major axis and (ii) second and third dimensions aligned perpendicular to the major axis and each other, where the first dimension is shorter than the second and third dimensions and (b) each adjacent pair of cavities is coupled by an inter-cavity slot, (2) an RF inlet that couples a received RF signal to a first cavity at a first end of the plurality of cavities, and (3) an RF outlet that couples a filtered RF signal from a second cavity at a second end of the plurality of cavities externally to the filter. Various other filters and manufacturing methods thereof are also disclosed.

Abstract: A method for producing a waveguide in a multilayer substrate involves producing at least one cutout corresponding to a lateral course of the waveguide in a surface of a first layer arrangement comprising one or a plurality of layers. A metallization is produced on surfaces of the cutout. A second layer arrangement comprising one or a plurality of layers is applied on the first layer arrangement. The second layer arrangement comprises, on a surface thereof, a metallization which, after the second layer arrangement has been applied on the first layer arrangement, is arranged above the cutout and together with the metallization on the surfaces of the cutout forms the waveguide.

Abstract: A method for determining angular orientation of an object in two or more directions. The method includes: generating a scanning polarized RF source signal; receiving the scanning polarized RF source signal at one or more cavities of a sensor disposed on the object; measuring the scanning polarized RF source signal at a first portion of the sensor; reflecting the scanning polarized RF source signal toward a second portion of the sensor; measuring the scanning polarized RF source signal at the second portion of the sensor; and determining the angular orientation of the object in the two or more directions based on the measured signal at the first and second portions of the sensor.

Abstract: Disclosed is a ridge guide waveguide including a conductive base, a conductive ridge protruding upward from the conductive base and extending along a predetermined wave transmission direction, an upper conductive wall located over the conductive base and the conductive ridge and spaced apart from the conductive ridge by a gap, and an electromagnetic bandgap structure arranged adjacent to the conductive ridge between the conductive base and the upper conductive wall.

Abstract: A radar system includes a split-block assembly unit comprising a first portion and second portion, where the first portion and the second portion form a seam. The radar system further includes a plurality of ports located on a bottom side of the second portion opposite the seam. Additionally, the radar system includes a plurality of radiating elements located on a top side of the first portion opposite the seam. The plurality of radiating elements is arranged in a plurality of arrays. The plurality of arrays includes a set of multiple-input multiple-output (MIMO) transmission arrays, a set of synthetic aperture radar (SAR) transmission arrays, and at least one reception array. Further, the radar system includes a set of waveguides configured to couple each array to a port.

Abstract: A new two-probe waveguide slide screw load-pull tuner of which the probes share the same waveguide section; they are inserted diametrically at fixed depth into facing each other slots on opposite broad walls of the waveguide. The tuner does not have cumbersome adjustable vertical axes controlling the penetration of the probes and its low profile is optimized for on-wafer operations. The carriages holding the probes are moved along the waveguide using electric stepper motors or linear actuators.

Abstract: A waveguide includes a dielectric substrate, a first conductor layer and a second conductor layer formed on a lower surface and an upper surface thereof, a pair of side wall parts forming side walls of both sides of the waveguide, and a feed part feeding an input signal to the waveguide. The feed part includes a feed terminal formed on the lower surface of the dielectric substrate and does not contact the first conductor layer, a first via conductor connected at a lower end thereof to the feed terminal, a first connection pad connected to an upper end of the first via conductor, and second via conductors that are each connected at a lower end thereof to the first connection pad. The sum of the cross-sectional areas of the second via conductors is greater than the sum of the cross-sectional area of the first via conductor.

Abstract: A door assembly for a microwave reactor including a microwave waveguide to direct microwaves from an external microwave source to inside the microwave reactor, and having a waveguide interface for preventing backflow of a process gas into the waveguide; an inlet for entry of matter to be treated in the microwave reactor; a first seal at the periphery of the door assembly to sealably interface with a static front of the microwave reactor; a second seal inserted into a groove on an inside face of the door assembly to sealably interface with an opening of a microwave reactor drum, the groove having a width of about 12.9 inches (32.766 cm) divided by an integer, and the second seal configured to prevent solids and liquids from flowing outside of the reactor drum; and a ring choke to contact a choke arranged on the periphery of the opening of the reactor drum.

Abstract: Embodiments of the present disclosure use a customizable ganged waveguide that comprises a top metal plate and a bottom metal plate with trenches that come together in a way so as to form waveguide channels. The waveguide assembly of the present invention also comprises a waveguide adapter affixed to a first end of the ganged waveguide and operable to conduct the signal to a tester. Further, it comprises an air barrier affixed to a second end of the ganged waveguide to prevent air from flowing from the ganged waveguide to a printed circuit board connected at the second end. Finally, it comprises a tuning plate comprising double ridge slots configured to allow maximal signal to be transferred to the printed circuit board from the ganged waveguide.

Abstract: A radio frequency waveguide communication system includes a guided electromagnetic transmission network, and a cooling air source. The guided electromagnetic transmission network includes one or more remote node in fluid communication with one or more waveguides. The cooling air source is in fluid communication with the guided electromagnetic transmission network and is configured to provide pressurized cooling air to the waveguide. The waveguides direct the pressurized cooling air to the remote node.

Abstract: An illustrative example embodiment of an antenna device includes a substrate, a plurality of antenna elements supported on the substrate, an integrated circuit supported on one side of the substrate, and a metallic waveguide antenna situated against the substrate. The metallic waveguide antenna includes a heat dissipation portion in a thermally conductive relationship with the integrated circuit. The heat dissipation portion is configured to reduce a temperature of the integrated circuit.

Abstract: A reactive beamformer includes a radiator disposed within a substrate and configured to radiate a received electromagnetic signal, a plurality of receptors disposed within the substrate, each of the plurality of receptors configured to receive a portion of the radiated electromagnetic signal, and a plurality of signal lines. Each signal line of the plurality of signal lines is coupled to a respective receptor of the plurality of receptors to convey the portion of the radiated electromagnetic signal from the respective receptor and to provide the portion of the radiated electromagnetic signal to an output.

Abstract: A method for constructing a vehicular radar sensor includes providing antenna structure and a printed circuit board having a first layer and a second layer with a copper layer disposed between the first and second layers. The antenna structure includes transmitting antennas that are operable to transmit radio signals, and receiving antennas that receive radio signals transmitted by the transmitting antennas and reflected from an object. The first layer is joined to a first side of the copper layer and the second layer is joined to a second side of the copper layer, with the copper layer spanning between and contacting opposed surfaces of the first and second layers. At least one waveguide is established through the copper layer. Electronic circuitry is disposed at the first layer of the printed circuit board and at least part of the antenna structure is disposed at the second layer of the printed circuit board.

Abstract: Disclosed herein are methods and circuits that prevent energy that would produce a spurious resonance from lumped, distributed or waveguide circuit elements by using for example a low pass filter with a cut-off below the first spurious resonance frequency and bypassing the energy at frequencies at or above the first spurious resonance frequency through a secondary path. This secondary path is high pass in nature, with a cutoff substantially similar to the low pass filter. The two paths are combined at the common output, using a lowpass matching network.

Abstract: An over-the-air measurement system for performing over-the-air measurements on a device under test is described. The measurement system comprises a measurement device having several measurement antennas, several waveguides, wherein at least one waveguide is assigned to each measurement antenna, several waveguide-to-cable adapters, and a positioning unit assigned to the measurement antennas. The number of the waveguide-to-cable adapters is at least identical to the number of the measurement antennas. The positioning unit is configured to move the measurement antennas with respect to the waveguide-to-cable adapters.

Abstract: A device for receiving and re-radiating electromagnetic signals. The device includes at least a wave guide with a first set of slot radiators for receiving electromagnetic signals, and a second set of slot radiators for transmitting electromagnetic signals generated on the basis of the received electromagnetic signals in the waveguide. The first set of slot radiators includes one or more slot radiators, and the second set of slot radiators includes one or more slot radiators. The device also relates to a method for receiving and re-radiating electromagnetic signals by a device including at least a waveguide, and the use of the device as a repeater of electromagnetic signals, for transferring electromagnetic signals through a structure, and/or as a building product.

Abstract: The present disclosure provides a waveguide-excited terahertz microstrip antenna. The antenna includes a dielectric substrate, a ground plate, a rectangular waveguide, a metal pin, and a radiation patch. The dielectric substrate has a first surface and a second surface opposite to the first surface. The ground plate is located on the first surface of the dielectric substrate and defines a coupling slit. The rectangular waveguide is located on a surface of the ground plate away from the dielectric substrate and extended substantially along a first direction parallel to the first surface. The metal pin is located inside the rectangular waveguide, and is in contact with the ground plate and substantially perpendicular to the ground plate. The radiation patch is located on the second surface of the dielectric substrate.

Abstract: Provided is a structure configured to electrically connect multi-layer dielectric waveguides, each including a dielectric waveguide formed of conductor patterns and vias in a laminating direction of the multi-layer dielectric substrate, in which the vias for forming part of a waveguide wall of each of the dielectric waveguides are arranged in a staggered pattern in the multi-layer dielectric substrate side having choke structures formed so as to electrically connect the waveguides to each other.

Abstract: An antenna comprising: a variable dielectric constant (VDC) layer; a plurality of radiating patches provided over the VDC layer; a plurality of signal lines, each terminating in alignment below one of the radiating patches; a plurality of control lines, each corresponding to one of the signal lines; a ground plane; wherein the VDC layer comprises a plurality of liquid crystal sublayers stacked on each other.

Abstract: A TFT substrate includes a gate metal layer including a gate electrode of a TFT and a patch electrode, a gate insulating layer formed on the gate metal layer and including a first opening at least reaching the patch electrode, a source metal layer formed on the gate insulating layer, and including a source electrode of the TFT, a drain electrode, and a drain extending section extending from the drain electrode, an interlayer insulating layer formed on the source metal layer, and including a second opening overlapping the first opening when viewed from a normal direction of a dielectric substrate and a third opening at least reaching the drain extending section, and a conductive layer formed on the interlayer insulating layer and including a patch drain connection section. The patch drain connection section is in contact with the patch electrode within the first opening and in contact with the drain extending section within the third opening.

Abstract: Aspects of the subject disclosure may include, for example, a transmission medium for propagating electromagnetic waves. The transmission medium can include a core for propagating electromagnetic waves guided by the core without an electrical return path, a rigid material surrounding the core, wherein an inner surface of the rigid material is separated from an outer surface of the core, and a conductive layer disposed on the rigid material. Other embodiments are disclosed.

Abstract: A networking system includes a transmitter, a waveguide and a receiver. The transmitter is configured to generate a millimeter-wave signal carrying data. The waveguide is transmissive at millimeter-wave frequencies and is configured to receive the millimeter-wave signal from the transmitter, and to guide the millimeter-wave signal from the transmitter to a downstream location by having a dielectric constant that varies over a transversal cross-section of the waveguide in accordance with a predefined profile. The receiver is configured to receive the millimeter-wave signal guided by the waveguide, and to extract the data carried by the received millimeter-wave signal.

Abstract: In accordance with an embodiment of the present disclosure, there is provided a technique of using probe fed apertures to realize a waveguide feeding network that can be divided both parallel to the surface, and on different levels, of a co-fired ceramic substrate, such as a low temperature co-fired ceramic (LTCC) substrate. A horizontal feed network is divided into several sections, which can be stacked vertically in various different locations and on different layers within the substrate, and are connected by probe-fed apertures. In this way, waveguide dividing can be performed in directions that are parallel to the surface of the substrate and on different levels of the substrate, thereby increasing the efficiency of the use of the substrate volume and permitting dividing and combining of inputs and outputs in a more flexible manner.

Abstract: Embodiments herein relate to a fully integrated broadband interconnect. The system comprises a first integrated circuit, a second integrated circuit, and a coupler structure to connect the first and second integrated circuits, where the coupler structure includes a base portion and a top portion that are connected by two vertical walls. The top portion has a gap that increases a strength of a transverse electric field across the gap when the coupler structure is operating in an odd higher order mode that is horizontally polarized, where the coupler structure is full of a dielectric material, and where the cross-sectional width of the coupler structure is tapered in a direction of wave propagation. The system further comprises a dielectric waveguide attached to the top portion of the coupler structure, where the dielectric waveguide supports the odd higher order mode and an even higher order mode.

Abstract: In accordance with one or more embodiments, a method includes: receiving, at a stranded cable, a communication signal and a medium voltage power signal; propagating, by the stranded cable, the medium voltage power signal as an electrical signal utilizing an electrical return path; and propagating, by the stranded cable and responsive to the communication signal, guided electromagnetic waves, wherein the guided electromagnetic waves are guided by an interstice between uninsulated strands of the stranded cable and propagate within the stranded cable without requiring the electrical return path.

Abstract: An illustrative example electronic device includes a substrate integrated wave guide (SIW) comprising a substrate and a plurality of conductive members in the substrate. An antenna member is situated at least partially in the substrate in a vicinity of at least some of the plurality of conductive members. A signal generator has a conductive output electrically coupled with the antenna member. The antenna member radiates a signal into the SIW based on operation of the signal generator.

Abstract: A horn antenna comprises an electrically conductive shell having an inner surface, a cavity formed in the shell, an aperture defined at one end of the cavity, a throat section coupled to the electrically conductive shell in communication with another end of the cavity opposite the aperture, and a spatially and frequency dependent radio frequency (RF) attenuator disposed within the cavity, such that an attenuation of RF energy propagating through the cavity between the throat section and the aperture more rapidly increases in an outward direction towards the inner surface of the electrically conductive shell as the frequency of the RF energy increases.