Abstract: An apparatus is provided for signal communication. This signal communication apparatus includes a waveguide with an internal channel. The internal channel includes a plurality of channel segments interconnected at a junction. The waveguide includes a first surface and a second surface. The first surface and the second surface partially form a peripheral boundary of the internal channel at the junction. The first surface meets the second surface at a first corner. The first surface is angularly offset from the second surface by an obtuse angle.

Abstract: An exemplary phase shifter is a waveguide with multiple alternate paths for waves. The phase shifter includes at least two alternative paths, one straight and one curved. Rounding, chamfer, or a combination of both are used at the corners where the path transitions from the straight waveguide section to the curved waveguide section or vice versa.

Abstract: According to one embodiment, a waveguide bend includes a metal block. The metal block includes a first waveguide, a second waveguide and a third waveguide. The first waveguide, the second waveguide and the third waveguide are integrally formed. The second waveguide includes a bend at which a propagation direction of a radio wave is changed. An opening size of the second waveguide is smaller than an opening size of the first waveguide. The third waveguide is provided between the first waveguide and the second waveguide. An opening size of the third waveguide is smaller than the opening size of the first waveguide and is larger than the opening size of the second waveguide.

Abstract: Various embodiments provide for waveguide assemblies which may be utilized in wireless communication systems. Various embodiments may allow for waveguide assemblies to be assembled using tools and methodologies that are simpler than the conventional alternatives. Some embodiments provide for a waveguide assembly that comprises a straight tubular portion configured to be shortened, using simple techniques and tools, in order to fit into a waveguide assembly. For instance, for some embodiments, the waveguide assembly may be configured such that the straight portion can be shortened, at a cross section of the portion, using a basic cutting tool, such a hacksaw. In some embodiments, the straight portion may be further configured such that regardless of whether the straight tubular portion is shortened, the waveguide assembly remains capable of coupling to flanges, which facilitate coupling the straight tubular portion to connectable assemblies, such as other waveguide assemblies, radio equipment, or antennas.

Abstract: Aspects of the subject disclosure may include, for example, a transmission device that includes at least one transceiver configured to modulate data to generate a plurality of first electromagnetic waves in accordance with channel control parameters. A plurality of couplers are configured to couple at least a portion of the plurality of first electromagnetic waves to a transmission medium, wherein the plurality of couplers generate a plurality of second electromagnetic waves that propagate along the outer surface of the transmission medium. A training controller is configured to generate the channel control parameters based on channel state information received from at least one remote transmission device. Other embodiments are disclosed.

Abstract: Aspects of the subject disclosure may include, for example, a transmission device that includes at least one transceiver configured to modulate data to generate a plurality of first electromagnetic waves in accordance with channel control parameters. A plurality of couplers are configured to couple at least a portion of the plurality of first electromagnetic waves to a transmission medium, wherein the plurality of couplers generate a plurality of second electromagnetic waves that propagate along the outer surface of the transmission medium. A training controller is configured to generate the channel control parameters based on channel state information received from at least one remote transmission device. Other embodiments are disclosed.

Abstract: A system for triggering improvised explosive devices (IEDs) with an alternating magnetic field. In one embodiment, the magnetic field is produced by a magnetic field projector in the shape of one-half of a torus, the half-torus being composed of several conductive segments referred to as toroidal wedges. A poloidal current flows in each toroidal wedge, producing a magnetic field that is projected by the half-torus. The magnetic field may induce a current, producing heating, in a conductive loop in an IED and triggering the IED.

Abstract: In a gap-mode waveguide embodiment, an interior gap in a tubular waveguide principally condenses a dominant gap mode near the interior gap, and an absorber dissipates electromagnetic energy away from the gap mode. In this manner, the gap mode may dissipate relatively little power in the absorber compared to other modes and propagate with lesser attenuation than all other modes. A gap mode launched into a gap-mode waveguide may provide for low-loss, low-dispersion propagation of signals over a bandwidth including a multimode range of the waveguide. Gap-mode waveguide embodiments of various forms may be used to build guided-wave circuits covering broad bandwidths extending to terahertz frequencies.

Abstract: A waveguide-configuration adapter is provided. The waveguide-configuration adapter includes a horizontal waveguide and a vertical waveguide. The horizontal waveguide includes a first-interface port spanning a first X-Y plane and a first-coupling port spanning a Y-Z plane with a first-coupling-port width parallel to the y axis. The vertical waveguide includes a second-interface port spanning a second X-Y plane and a second-coupling port spanning a third X-Y plane with a second-coupling-port width parallel to the x axis. When an E-field is input at the first/second coupling port in the plane of the first/second coupling port, respectively, and oriented perpendicular to the first/second coupling-port width, respectively, the E-field is output from the second/first coupling port, respectively, in the plane of second/first coupling port, respectively, and oriented perpendicular to the second/first coupling-port width, respectively.

Abstract: A waveguide for transmission of data signals therealong. Data signals are typically received from and/or transmitted to a remote location and subsequently passed to or emitted from the apparatus which allows the data to be processed. The waveguide includes a channel which has a cross-sectional shape, the angular orientation of which is changed at least one point along the length of the same so as to provide a waveguide which is less sensitive to interferences. The waveguide, in one embodiment, can also include recessed portions and/or ridges along the length of the channel which ensures that the waveguide can be formed in a more reliable and controlled manner.

Abstract: A waveguide structure including (i) a base that has a mounting surface, (ii) a metal plate member that has elasticity, that is stacked on the mounting surface, and that functions together with the base to constitute a waveguide, (iii) a positioning mechanism that is constituted by a positioning pin that is disposed so as to protrude from the base and an interfitting portion that is formed on the plate member, and that is fitted together with the positioning pin, the positioning mechanism positioning the plate member on the mounting surface of the base and also restricting movement along the mounting surface by fitting together of the positioning pin and the interfitting portion, and (iv) a holder that holds the plate member in a state of close contact with the mounting surface by pressing the plate member so as to generate a reaction force in the plate member.

Abstract: The present invention relates to a transition arrangement comprising two surface-mountable waveguide parts and a dielectric carrier material with a metallization and a ground plane provided on a respective first main side and second main side Surface-mountable waveguide parts comprise a first wall, a second wall, and a third wall, which second and third walls are arranged to contact a part of the metallization, all the walls together essentially forming a U-shape, the surface-mountable waveguide parts also comprising respective bend parts. The metallization on the first main side is removed such that a first aperture and a second aperture are formed, the apertures being enclosed by a frame of via holes electrically connecting the ground plane with the metallization, the bend parts being fitted such that the apertures permit passage of a microwave signal propagating via the bend parts. Then the dielectric carrier material itself acts as a waveguide transition between the first aperture and the second aperture.

Abstract: In an exemplary embodiment, a dual-band four-port orthomode transducer (OMT) is molded or cast. The OMT may be external to a transceiver housing or included as an integrated portion of the transceiver housing or a drop-in module. In an exemplary embodiment, a four-port OMT is formed from two pieces, the two pieces having a joint adjacent to or aligned to the axis of the common port. In an exemplary embodiment, the OMT is substantially planar and formed of a split-block embodiment. The two OMT pieces are joined and held together with a plurality of discrete fasteners. Furthermore, the OMT is configured to switch polarizations. The polarization switching is initiated using a remote signal and can facilitate load balancing.

Abstract: Various embodiments provide for waveguide assemblies which may be utilized in wireless communication systems. Various embodiments may allow for waveguide assemblies to be assembled using tools and methodologies that are simpler than the conventional alternatives. Some embodiments provide for a waveguide assembly that comprises a straight tubular portion configured to be shortened, using simple techniques and tools, in order to fit into a waveguide assembly. For instance, for some embodiments, the waveguide assembly may be configured such that the straight portion can be shortened, at a cross section of the portion, using a basic cutting tool, such a hacksaw. In some embodiments, the straight portion may be further configured such that regardless of whether the straight tubular portion is shortened, the waveguide assembly remains capable of coupling to flanges, which facilitate coupling the straight tubular portion to connectable assemblies, such as other waveguide assemblies, radio equipment, or antennas.

Abstract: A waveguide corner including a first rectangular waveguide and a second rectangular waveguide. An end face of the second rectangular waveguide is made open to an H-plane wall of the first rectangular waveguide and the H-plane walls of the second rectangular waveguide are disposed along the pipe axis of the first rectangular waveguide. Accordingly, planes of polarization of electromagnetic waves being propagated in the first and second rectangular waveguides are made perpendicular to each other.

Abstract: An improved 90° waveguide bend has the following features: the waveguide bend has two waveguide connectors located perpendicularly to each other, the waveguide connectors have a square internal cross section having an edge length (a), between the two waveguide connectors there is provided an angular portion producing the 90° change in direction, the angular portion has externally to the 90° change in direction a chamfer as a delimiting wall for the waveguide bend, the waveguide channel being outwardly delimited by the chamfer, and the chamfer has in the plane of curvature a length corresponding to the edge length (a) of the waveguide connectors which are square in cross section, ±less than 0.5%.

Abstract: In an exemplary embodiment, a dual-band four-port orthomode transducer (OMT) is molded or cast. The OMT may be external to a transceiver housing or included as an integrated portion of the transceiver housing or a drop-in module. In an exemplary embodiment, a four-port OMT is formed from two pieces, the two pieces having a joint adjacent to or aligned to the axis of the common port. In an exemplary embodiment, the OMT is substantially planar and formed of a split-block embodiment. The two OMT pieces are joined and held together with a plurality of discrete fasteners. Furthermore, the OMT is configured to switch polarizations. The polarization switching is initiated using a remote signal and can facilitate load balancing.

Abstract: A junction (100) for connecting two waveguides (102, 104) having a first angular offset (?) between longitudinal symmetry axes of their cross-sections, said junction (100) comprising a first interface and a second interlace for connecting said waveguides (102, 104). The junction further comprises at least a first transformer section (106) and a second transformer section (108), both having cross-sections of substantially rectangular shape, and both having said first angular offset (?) between longitudinal symmetry axes of their cross-sections. Each of said transformer sections (106, 108) has two protruded ridges (202, 204, 206, 208) on its opposite walls.

Abstract: A coaxial transition includes a first conductor aligned along a first axis. The transition also includes a ground shield surrounding the first conductor such that a first gap exists between the first conductor and the ground shield. An electric field radiates between the first conductor and the ground shield through the first gap. The transition further includes a second conductor aligned along a second axis and coupled to the first conductor. The second conductor forms a second gap between the second conductor and a portion of the ground shield. A first portion of the electric field radiates between the second conductor and the ground shield through the second gap. The transition also includes a top ground plane aligned substantially parallel to the second conductor. A third gap exists between the top ground plane and the second conductor. The second gap and the third gap are substantially parallel with the second conductor therebetween.

Abstract: The disclosure provides a corner waveguide including a first straight waveguide portion for transmitting an electromagnetic wave, a second straight waveguide portion for transmitting an electromagnetic wave to a direction different from the transmitting direction of the electromagnetic wave of the first straight waveguide portion, and a corner waveguide portion connecting the first and second straight waveguide portions. An outside inner wall of the corner waveguide portion has inclined planes inclined at at least three or more different angles with respect to a plane including a longitudinal axis of the waveguide portion.

Abstract: An LSE mode, which is a parasitic mode, can be effectively suppressed by a simple structure, and a reduction in size and weight can be thereby facilitated. Further, a metal body 3 is arranged in the vicinity of a dielectric waveguide 1 of an NRD guide to suppress the LSE mode, the NRD guide being configured to propagate electromagnetic waves through the dielectric waveguide 1 which is sandwiched between parallel conductor plates with a gap of less than a ½ wavelength. This metal body 3 has an arbitrary shape, and may have a discoid shape, an elliptic shape or a prismatic shape. Furthermore, an even distance d is maintained between the metal body 3 and the dielectric waveguide 1, and a phase constant difference can be suppressed by changing this distance d.

Abstract: A waveguide corner including a first rectangular waveguide and a second rectangular waveguide. An end face of the second rectangular waveguide is made open to an H-plane wall of the first rectangular waveguide and the H-plane walls of the second rectangular waveguide are disposed along the pipe axis of the first rectangular waveguide. Accordingly, planes of polarization of electromagnetic waves being propagated in the first and second rectangular waveguides are made perpendicular to each other.

Abstract: A compact circular waveguide system can connect circular waveguides through a bend while avoiding excessive interaction between the orthogonal modes of the circular waveguides. A compact bend system with circular waveguide input and output can be achieved by providing short quarter wave transformers. The quarter wave transformers can be positioned at the transitions between the circular waveguides and a single-mode quasi-rectangular waveguide segment. Within the single-mode quasi-rectangular waveguide segment, a bend can be formed without concern for mixing of the orthogonal modes of the circular guided wave. The undesired mode of propagation can be substantially reduced or eliminated within the quarter wave transformers with a resistive mode suppressor. The compact system can be machined out of a single block of material from the outside flange faces.

Abstract: A compact circular waveguide system can connect circular waveguides through a bend while avoiding excessive interaction between the orthogonal modes of the circular waveguides. A compact bend system with circular waveguide input and output can be achieved by providing short quarter wave transformers. The quarter wave transformers can be positioned at the transitions between the circular waveguides and a single-mode quasi-rectangular waveguide segment. Within the single-mode quasi-rectangular waveguide segment, a bend can be formed without concern for mixing of the orthogonal modes of the circular guided wave. The undesired mode of propagation can be substantially reduced or eliminated within the quarter wave transformers with a resistive mode suppressor. The compact system can be machined out of a single block of material from the outside flange faces.

Abstract: Provided are an enhanced structure of a coplanar waveguide that is a kind of transmission line used for optical communication for radio frequency (RF), and an optical communication module employing the same. While having a basic structure including a conductive strip and ground strips at both sides of the conductive strip on a dielectric substrate, the coplanar waveguide has the structure in which metal patterns of a portion of the conductive strip located around points where an RF propagation direction is changed and of a portion of an inside ground strip are removed to make electrical lengths of an outside ground strip and the inside ground strip similar each other. Using the coplanar waveguide, it is possible to fabricate an optical module that has an optimized RF characteristic and also can freely change an RF propagation direction of several tens GHz, without an additional process.

Abstract: An improved 90° waveguide bend has the following features: the waveguide bend has two waveguide connectors located perpendicularly to each other, the waveguide connectors have a square internal cross section having an edge length (a), between the two waveguide connectors there is provided an angular portion producing the 90° change in direction, the angular portion has externally to the 90° change in direction a chamfer as a delimiting wall for the waveguide bend, the waveguide channel being outwardly delimited by the chamfer, and the chamfer has in the plane of curvature a length corresponding to the edge length (a) of the waveguide connectors which are square in cross section, ± less than 0.5%.

Abstract: A filter including a body on which a waveguide groove, whose one surface is open, is formed in a U-shape and a plurarity of inductive resonant windows are provided along a longitudinal direction of the waveguide groove at a predetermined interval in the waveguide groove; and a cover being provided on a top surface of the body so as to cover the surface being open, wherein the plurality of inductive resonant windows are provided in such a manner that a cavity, which is enclosed by two of the plurality of inductive resonant windows being adjacent, the body and cover, resonates at a predetermined frequency and passes a electromagnetic wave in a predetermined frequency band and wherein one end of the U-shaped waveguide groove is an input terminal and other end is an output terminal, and the input terminal and output terminal are formed on a same surface.

Abstract: A dielectric waveguide which comprises a first single crystal magnesium oxide block having a surface of face (001), (100) or (010) and a first copper oxide superconducting film formed on the above-described surface in a c-axis crystal orientation perpendicular to the surface, and a method of production thereof are provided.

Abstract: Provided is a waveguide interconnection apparatus making rectangular interconnecting portions to be a curved structure, whereby it is possible to reduce a signal reflection and a signal loss due to a mismatch occurred from a discontinuous portion where waveguides are perpendicularly connected to each other, and fabricate package products having excellent performances compared to that of the prior art in the same chip and structure.

Abstract: An E-plane filter comprises a housing having a waveguide filter channel and a septum defining a plurality of couplers spaced apart along the length of the filter channel, thereby forming a resonator cavity between each adjacent coupler. The portion of the filter channel which accommodates the couplers and each resonator cavity is curved or otherwise changes direction in a plane transverse to the channel walls.

Abstract: Provided is a waveguide interconnection apparatus making rectangular interconnecting portions to be a curved structure, whereby it is possible to reduce a signal reflection and a signal loss due to a mismatch occurred from a discontinuous portion where waveguides are perpendicularly connected to each other, and fabricate package products having excellent performances compared to that of the prior art in the same chip and structure.

Abstract: The invention reduces the size of waveguide circuits. The invention proposes to change the cross section of a waveguide in a curved part. Thus, a curved element according to the invention makes it possible at the same time to make a change in waveguide cross action.

Abstract: A system for transmitting wireless communications within ductwork. The system includes a plurality of transmitter devices for introducing electromagnetic radiation into the ductwork such that the ductwork acts as a waveguide for the electromagnetic radiation, said transmitter devices comprising a transmitter array, wherein the transmitter devices are configured to introduce the electromagnetic radiation using multiple propagation modes. The system also includes a plurality of receiver devices for detecting the electromagnetic radiation within the ductwork, said receiver devices comprising a receiver array.

Abstract: A dielectric waveguide which comprises a first single crystal magnesium oxide block having a surface of face (001), (100) or (010) and a first copper oxide superconducting film formed on the above-described surface in a c-axis crystal orientation perpendicular to the surface, and a method of production thereof are provided.

Abstract: A vertical transition device for differential stripline paths, connects differential microstrip paths on a horizontal plane with differential triplate paths on another horizontal plane in a multilayered architecture. The differential microstrip paths include a pair of differential microstrip lines. The differential triplate paths include a pair of triplate lines. The differential microstrip lines are connected with the differential triplate lines by via-holes within the transition device, respectively.

Abstract: An all-dielectric coaxial waveguide comprising a dielectric core region; an annulus of dielectric material, surrounding the core region, in which electromagnetic radiation is confined; and an outer region of cylindrically coaxial dielectric shells of alternating indices of refraction surrounding the annulus. The core region and the outer region have an average index of refraction which is higher than the index of refraction of the annulus.

Abstract: The invention reduces the size of waveguide circuits. The invention proposes to change the cross section of a waveguide in a curved part. Thus, a curved element according to the invention makes it possible at the same time to make a change in waveguide cross section.

Abstract: A small-sized cylindrical waveguide having a low reflection characteristic is disclosed. An inner bent portion connects cavities of first and second waveguide portions in a range of not larger than one-fourth of the diameter of the cavities on each of an extension line of an innermost wall portion in the cavity of the first waveguide portion and an extension line of an innermost wall portion in the cavity of the second waveguide portion, from an intersecting point of both extension lines.

Abstract: A high-frequency dielectric waveguide line comprising a dielectric substrate with two conductor layers on its two surfaces, and a plurality of rows of through conductors in the substrate connecting the two conductor layers. The distances between the through conductors in each row are not more than half of the wavelength of the signal transmitted in the transmission direction of the waveguide. The waveguide line has a branching portion where a first waveguide line having a width d branches into second and third parallel waveguide lines both of width d. The portion of the waveguide at the branching point has a width of A, where 2d≦A≦3d. The first, second and third waveguide lines are connected without abrupt width enlargement. The branching waveguide line have small transmission losses for high-frequency signals.

Abstract: A feed that provides circularly polarized microwave energy such as for energizing a microwave oven cavity. The feed includes a transformer to match a linearly polarized rectangular waveguide to a polarization waveguide section which may be circular or square in cross section. The polarization waveguide section contains an asymmetrical element that provides symmetry about a plane only. The asymmetrical element therefore introduces a difference in microwave electrical phase for polarizations which are respectively parallel to and perpendicular to the symmetry plane. A second waveguide section having a bend is also used in the feed assembly. The second waveguide section, which may for example be a bent section of circular waveguide, also presents an electromagnetic symmetry about a plane only. As a result, the two waveguide sections operating together provide circularly polarized energy at constant magnitude but continually rotating phase.

Abstract: A technique for passive suppression of arcs within a microwave frequency waveguide section. The waveguide is configured to have a bend at a point where the naturally, relatively high location occurs within the run. The bend at the high point causes arcs to be trapped as heat naturally collects within the waveguide at such predictable locations. Vent holes formed in the exterior portion of the waveguide at this point allow trapped hot air gases to escape, and cause the arc to be drawn towards the sidewall of the waveguide at a point where the voltage approaches zero. Presenting this region of zero voltage to the arc causes the arc to extinguish itself.

Abstract: A waveguide filter includes one or more resonator cavities which extend between an input to the filter and an output from the filter. Each resonator cavity in the filter has a center line with a chosen extension and a mechanical length. The mechanical length of the center line of each resonator cavity forms one of the parameters that determine the electrical length of the resonator cavity. The filter forms part of a microwave unit. At least one of the resonator cavities of the filter has a curved extension with respect to its center line.

Abstract: In a millimeter wave module or the like having both a normal NRD guide and a hyper NRD guide, a conversion portion structure for non, radiative dielectric waveguides of different types has excellent conversion characteristics at the connection between the two types of NRD guides. In a first conversion portion, the width of a dielectric strip is changed from the width of a dielectric strip in the hyper NRD guide portion to the width of a dielectric strip in the normal NRD guide portion, grooves of approximately the same depth as grooves in the hyper NRD guide are provided extending as far as the second conversion portion, and in a third conversion portion, the width of these grooves widens perpendicular to the propagation direction of electromagnetic waves and parallel to the face of conductive plates. According to this structure, guide conversion can be achieved with low radiation in a predetermined frequency band.

Abstract: A bending mechanism for flexible waveguide uses a combination of an elongate arm (1), two short bracket arms (3 & 7) and a gear train (5, 11, 13 & 9) linking the bracket arms to bend a flexible waveguide (24) over a range of positions. The bend is formed to the shape of a circular arc the radius of which varies with the position. Each short bracket arm is pivotally connected (15 & 17) to a respective end of the elongate arm and to a respective one of the waveguide's two end flanges (23 & 25). Each bracket arm contains a gear that rotates with the respective bracket arm about the bracket arm's pivot; and an even number of gears interlinks those gears whereby pivotal movement of one of the flanges in a clockwise direction produces an effective relative pivotal movement of the other flange.

Abstract: A module equipped with a non-radiative dielectric waveguide in accordance with this invention comprises a pair of parallel flat conductors arranged at a space of 1/2 or below of a high frequency signal wavelength .lambda. and a dielectric strip extending between these parallel flat conductors. This dielectric strip is formed from a cordierite ceramic having a dielectric constant of 4.5 to 8, especially 4.5 to 6. Conversion of an electromagnetic wave of LSM mode to an electromagnetic wave of LSE is minimal. When the module has a dielectric strip having a steep curved portion having a small radius of curvature, the transmission is possible with a low loss, and the band width of a high frequency signal is broad.

Abstract: A waveguide device for transmitting and processing microwave signals includes a plate structure having recesses forming waveguides for the transmitting the microwave signals between microwave components. The plate structure includes a body plate and covering plates for connection to opposite surfaces of the body plate. The body plate and the covering plates form delimiting surfaces for the waveguides, and the microwave components can be positioned in the body plate or the covering plates.

Abstract: A small and inexpensive planar dielectric line that can be easily connected to electronic parts, such as ICs, and has smaller conduction losses. The planar dielectric line includes a dielectric substrate having first and second surfaces opposedly facing each other. A first slot having a predetermined width is interposed between first and second electrodes on the first surface of the dielectric substrate. A second slot having the same width as the first slot is disposed between third and fourth electrodes on the second surface of the dielectric substrate. The first and second slots opposedly face each other. The permittivity and the thickness of the dielectric substrate are determined so that a planar electromagnetic wave can propagate in a propagation region of the substrate interposed between the first and second slots while being substantially totally reflected on the first surface of the substrate adjacent to the first slot and the second surface of the substrate near the second slot.

Abstract: A dielectric waveguide has a dielectric member disposed between a pair of parallel conductor flat surfaces, such that a propagating region and a non-propagating region are formed. The spacing between the conductor flat surfaces in the non-propagating region is determined to be smaller than that in the propagating region. The above-mentioned spacings and the dielectric constant of the dielectric member are determined such that the cut-off frequency of the LSM.sub.01 mode propagating through the propagating region is lower than the cut-off frequency of the LSE.sub.01 mode and that electromagnetic waves of both the LSM.sub.01 mode and the LSE.sub.01 mode are cut-off in the non-propagating region, so that any transmission loss attributable to a mode conversion between the LSM.sub.01 mode and LSE.sub.01 mode occurring at, for example, a bend of the waveguide is eliminated so as to facilitate production of the waveguide having a desired bend angle and radius of curvature.

Abstract: The present invention is directed to a system for using the ductwork of a building for transmitting electromagnetic radiation. The system includes a device for introducing electromagnetic radiation into the ductwork such that the ductwork acts as a waveguide for the electromagnetic radiation. The system also includes a device for enabling the electromagnetic radiation to propagate beyond the ductwork. The present invention is also directed to a method for transmitting electromagnetic radiation using the ductwork of a building and a method for designing a system for transmitting electromagnetic radiation in the ductwork of a building.

Abstract: Apparatus and related methods for an easily manufactured evanescent mode band reject filter that provides high performance with minimal dependence on critical dimensions. According to one embodiment, the present invention provides a band reject filter including a waveguide having an input, an output, a first wall between the input and the output, and a second wall opposite the first wall. The first wall is part of a substantially solid first block, and the second wall is part of a substantially solid second block. The waveguide is capable of transmitting an electromagnetic radiation signal from the input to the output, where the signal is at an operating frequency above a waveguide cutoff frequency. The band reject filter also includes at least one cavity coupled directly to the first wall of the waveguide, where the cavity is a substantially cylindrical cavity formed in the first block.