Abstract: A flat-aperture waveguide sidewall-emitting antenna in a compact low-profile configuration and with the capability of radiating a beam of extremely high-power microwave (HPM) pulses in a directional manner is provided. High-power microwave antennas are essential technologies to microwave-based directed energy weapons (DEW). The flat-aperture waveguide sidewall-emitting antenna is especially well-suited to high-power microwave operation because of its relatively large aperture, which distributes the output power evenly over a large area, thus reducing the risk of microwave-induced air-breakdown or surface-breakdown that would other wise impede proper operation and degrade output beam formation.

Abstract: Location of an emitter using leaky cables. A two-channel receiver determines the location of an emitter by measuring the phase and/or amplitude difference between emitter signals received by leaky cables. In one embodiment, two leaky cables having different propagation velocities are used. In a second embodiment also suitable for use with fiber optic cables, two cables having the same propagation velocity are used, but have different lengths, the extra length being taken up by serpentine patterns or loops. A single cable in a loop may also be used. The leak points on the cables may be passive, or may be controlled RF switches.

Abstract: A radiated mode coaxial cable comprising an outer conductor provided with a periodic aperture array, comprising a plurality (n) of apertures or aperture sets, repeated along the length of said outer conductor whereas a constant spacing s separates the left end of the first aperture of one array and the left end of the first aperture of a next array, wherein each array comprises at least 10 apertures or aperture sets, whereas the global length L (in mm) of the apertures or aperture sets is larger than (10D/n)1/2 where D is the diameter of the cable (in mm) and whereas the aperture spacing (d) in between two successive apertures or aperture sets is larger than 1.5w where w is the aperture width in the cable axis direction, and wherein the spacing s between two successive aperture arrays is selected so that ?opt.1/(??r?0,866)<s<?opt.2/(??r?1), where ?opt.1 and ?opt.

Abstract: A transverse device array phase shifter includes an overmoded waveguide structure having a top conductive broad wall surface, a bottom conductive broad wall surface and opposed first and second conductive side wall surfaces. At least one transverse device array circuit is positioned in the waveguide circuit. Each circuit comprises a generally planar dielectric substrate having a microwave circuit defined thereon, and a plurality of spaced discrete phase shifter elements. The substrate is disposed within the waveguide structure generally transverse to the side wall surfaces. A bias circuit applies a voltage to reverse bias the phase shifter elements. The transverse device array phase shifter circuit causes a change in phase of microwave or millimeter-wave energy propagating through the waveguide structure.

Abstract: A waveguide portion has a waveguide with a rectangular section surrounded by a pair of narrow side plates opposed to each other, a pair of broad side plates extending along lengthwise directions of the pair of narrow side plates. A radiation portion is provided on one broad side plate of the pair of broad side plates of the waveguide portion, and has a plurality of slots for radiating an electromagnetic wave input into the waveguide portion externally from the one broad side plate. The waveguide portion includes a first waveguide member and a second waveguide member, and is constituted by joining the first waveguide member and the second waveguide member at edge portions extending in longitudinal directions thereof matching with central lines of the pair of broad side plates. The plurality of slots of the radiation portion has a first group of slots and a second group of slots defined respectively in the first waveguide portion and the second waveguide portion at predetermined intervals in a staggered manner.

Abstract: A flexible coaxial cable includes an inner conductor, and a dielectric layer generally surrounding the inner conductor. A tape outer conductor generally surrounds the dielectric layer, and does not underlie another electrically conductive layer such as a braided wire layer. The tape outer conductor may include a surface defining a plurality of indentations for minimizing damage to the tape outer conductor resulting from repeated flexing of the cable, and may define a plurality of apertures to enable generation of radiating waves during signal excitation of the cable.

Abstract: Asymmetric support for high frequency transmission lines. An asymmetrical support structure coaxially supports a center conductor over a ground plane using a dielectric material. Absorbing material between the dielectric and the outer conductor reduces the effects of high order modes.

Abstract: A waveguide portion has a waveguide with a rectangular section surrounded by a pair of narrow side plates opposed to each other, a pair of broad side plates extending along lengthwise directions of the pair of narrow side plates. A radiation portion is provided on one broad side plate of the pair of broad side plates of the waveguide portion, and has a plurality of slots for radiating an electromagnetic wave input into the waveguide portion externally from the one broad side plate. The waveguide portion includes a first waveguide member and a second waveguide member, and is constituted by joining the first waveguide member and the second waveguide member at edge portions extending in longitudinal directions thereof matching with central lines of the pair of broad side plates. The plurality of slots of the radiation portion has a first group of slots and a second group of slots defined respectively in the first waveguide portion and the second waveguide portion at predetermined intervals in a staggered manner.

Abstract: An RF coaxial cable with clad conductors includes an inner tubular conductor having a first base layer formed of a relatively higher conductivity material, and a first bulk layer formed of a relatively lower conductivity material. The first base layer of higher conductivity material extends over an area greater than an area of the first bulk layer to form first margin regions composed of only the higher conductivity material. The first margin regions of the first base layer of the higher conductivity material are joined together to form the inner tubular conductor with only the first margin regions of the higher conductivity material being joined. Also included is a dielectric material surrounding the inner conductor, an outer tubular conductor formed in the same manner as the inner conductor.

Abstract: An RF radiating cable includes a tubular inner conductor, a layer of foam dielectric material surrounding the inner conductor, and a burst-resistant internal layer of flame retardant material longitudinally wrapped about the foam material. A metallic outer conductor is longitudinally wrapped about flame retardant material, where the outer conductor having a plurality of apertures formed therein. A jacket of weather-proofing material is formed as an extruded layer surrounding the outer conductor.

Abstract: A FM CW cable guided radar for the detection and location of outdoor perimeter intruders. Helically wound outer conductors on coaxial transmit and receive transmission lines provide a slow wave structure to support the propagation of external electromagnetic fields. The two leaky coaxial lines are enclosed in an extruded plastic jacket with the outer conductors in continuous electrical contact along the length of the cable. A chirp frequency modulation provides a continuous target response having a baseband frequency that is proportional to the distance along the length of the cable. After location determination, the amplitude of the response is compared to a location specific threshold to determine if an intruder is present.

Abstract: The invention relates to a method for producing a microwave filter (700), comprising making at least one through-cutout (750) in a first electrically conductive plate (740) shaped as a rectangle, with a short side and a long side, inserting the first plate (740) between a second (710) and a third (730) electrically conductive plate (710), the first plate being arranged parallel to the second and the third plate, making electrical connections (794, 795) between said three plates for interconnecting those edge surfaces on the plates which coincide with the direction of propagation of the electrical signals, as a result of which a space comprising one or more cavities is formed. The first plate (740) is arranged so that the extent of its short side coincides with the E-field of the microwave signals when they propagate in the filter (700), and the extent of its long side coincides with the direction of propagation of the electrical signals.

Abstract: A flat radiating cable in which conductive layers are not adhered to a dielectric core. Each of the conductive layers comprises a resilient material which resists kinking and is capable of longitudinal translation with respect to the core and/or the other conductive layer.

Abstract: A radiating coaxial cable having a longitudinal axis comprises an inner conductor having a longitudinal axis wherein the axis of the inner conductor defines the axis of the cable. A dielectric material surrounds the inner conductor. A continuous outer conductor surrounds the dielectric in direct contact therewith and is spaced from the inner conductor. The outer conductor has a plurality of slots disposed therein. Adjacent slots are spaced in the axial direction a distance S. One or more adjacent slots are grouped together in a cell. The cable has a plurality of cells. Adjacent cells are angularly disposed from each other by an angle &agr;.

Abstract: A flat radiating cable in which conductive layers are not adhered to a dielectric core. Each of the conductive layers comprises a resilient material which resists kinking and is capable of longitudinal translation with respect to the core and/or the other conductive layer.

Abstract: A radiating coaxial radio-frequency cable is specified, that comprises an inner conductor, a dielectric surrounding the latter and a tubular outer conductor disposed above the latter and concentric with the inner conductor. In the outer conductor, mutually separated openings (5) are provided that are disposed in a mutually offset manner in the circumferential direction of the cable and, in the longitudinal direction of the latter, are disposed along surface lines extending mutually in parallel in rows (R1, R2, R3) extending over the entire length of the cable. All the openings (5) extend essentially in the circumferential direction of the cable.

Abstract: A radiating coaxial radio-frequency cable is specified, that comprises an inner conductor, a dielectric surrounding the latter and a tubular outer conductor disposed above the latter and concentric with the inner conductor. In the outer conductor, mutually separated openings (5) are provided that are disposed in a mutually offset manner in the circumferential direction of the cable and, in the longitudinal direction of the latter, are disposed along surface lines extending mutually in parallel in rows (R1, R2, R3) extending over the entire length of the cable. All the openings (5) extend essentially in the circumferential direction of the cable.

Abstract: A radiating coaxial cable includes an inner conductor, an electrical insulator located about a periphery of the inner conductor, and an outer conductor located about a periphery of the electrical insulator. The outer conductor defines groups of apertures spaced from each other a predetermined distance in the range of from about twice the longest operational wavelength of the cable to less than ten meters. The aperture groups are designed in such a way to excite a surface wave at low operating frequencies and a combination of surface and radiating waves at high operational frequencies.

Abstract: A radiating coaxial high frequency cable includes an inner conductor, insulation surrounding the same, and a tubular outer conductor which is concentric to the inner conductor and arranged over the insulation. The outer conductor includes openings, which are separated from each other and located in sections, which are arranged in uniform succession in the longitudinal direction of the cable. Each section has at least one first opening and the distance between the first openings of two neighboring sections is equivalent to half the wavelength of a first high frequency to be transmitted. To transmit frequencies, characterized by an integer multiple, without trouble, each section has at least a second opening in the outer conductor, whose distance from the first opening is equivalent to a fourth of the wavelength of the first high frequency to be transmitted.

Abstract: A leaky waveguide antenna array that receives and/or transmits electromagnetic signals includes a plurality of radiation waveguides disposed in parallel to each other on a surface plane to form the antenna array. A feed waveguide is located below the surface plane and provides an electromagnetic signal to the plurality of radiation waveguides and/or receives a plurality of electromagnetic signals from the plurality of radiation waveguides and provides a composite electromagnetic signal at an output of the feed waveguide. Each of the plurality of radiation waveguides has a waveguide axis and includes a plurality of apertures arranged in a direction of the waveguide axis. The feed waveguide includes a first section of waveguide having a first end connected to an input/output port. The first section of waveguide has a height substantially the same as the height of each of the plurality of radiation waveguides and the first section of waveguide has a second end coupled to a first junction point.

Abstract: A compact high gain VHF antenna for airborne synthetic aperture radar to detect targets concealed behind trees and forests. The antenna is formed by cutting a slotline in the middle of the top wall of a very thin waveguide along its axis. The waveguide can be folded and mounted on the underside of the wings of an aircraft with minimum protrusion and wing drag. The antenna produces a downward and side-looking beam with horizontal polarization for maximum foliage penetration and target detection. The antenna design can be scaled to any frequency for ground based and shipboard applications.

Abstract: In a radiating coaxial cable, the outer-conductor having a plurality of radiating apertures is wrapped in a tape of conducting material which covers some of the apertures. In one embodiment of the invention, the conductive tape is combined with a fire retardant tape so that one winding procedure will result in winding both the conductive tape and the fire retardant tape over the outer-conductor.

Abstract: A sensor cable formed of a center conductor surrounded by dielectric material and first and second layers. The first layer is formed of a gapped conductive material surrounding the dielectric material. The second layer has predetermined conductivity and at least covers the gaps in the conductive material of the first layer. The predetermined conductivity and thickness of the second layer is such that the skin depth in the second layer at an operating frequency of the cable is much greater than the thickness of the second layer, and inductive coupling into or out of the cable through gaps in the second layer is at least an order of magnitude greater than capacitive coupling into or out of the cable through gaps in the second layer.

Abstract: A radiating coaxial cable comprises an inner conductor, a layer of cellular foam dielectric material surrounding the inner conductor, and a single, continuous, corrugated outer conductor surrounding the dielectric foam layer in direct contact with it. The outer conductor forms at least one row of slots which are configured to produce a radiated field polarized perpendicularly to the axis of the cable to substantially avoid the radiation of a field polarized parallel to the axis of the cable and to provide coupling energy between the interior of the cable and the slots. In this way a substantially constant near-field pattern is produced along the length of the cable across the bandwidth of the cable.

Abstract: A leakage dielectric waveguide includes a housing made of plane-shaped electrical conductors located parallel to each other, and a dielectric strip for propagating a high-frequency wave between the parallel electrical conductors, wherein the dielectric strip is provided within the housing. The housing is arranged to be asymmetrical, thereby leaking and radiating a high-frequency wave propagating through the dielectric strip. The housing is preferably further composed of the plane-shaped parallel electrical conductors and a side wall. A plane antenna includes the above-mentioned leakage dielectric waveguide, and a projecting device for projecting the high-frequency wave toward a free space in response to a high-frequency wave being projected from the dielectric waveguide.

Abstract: A radiating waveguide comprises an elongated waveguide with a transverse cross-section dimensioned to carry only the dominant mode at a selected operating frequency. One wall of the waveguide forms a continuous non-resonant longitudinal slot or equivalent thereof to produce a radiated field polarized perpendicularly to the slot. The slot extends substantially parallel to the axis of the waveguide and has a transverse dimension that is sufficiently narrow to substantially avoid the radiation of a field polarized parallel to the slot.

Abstract: The line comprises a tubular outer conductor including apertures configured to form a periodic pattern (M) repeated along said outer conductor with a predetermined pitch (p). The periodic pattern has a length (L) equal to p/2.+-..DELTA., along a direction parallel to the axial direction of the line. The periodic pattern can be produced in various embodiments.

Abstract: A radio frequency communication system utilizing a radiating transmission line is disclosed. During normal operation, a mobile communication unit near the radiating transmission line can communicate with other mobile communication units near the transmission line as well as with the base station. The communication system is redundant in that if a portion of the communication system fails such that communication signals cannot be communicated through the fault the communication system will continue to operate and communication signals from any mobile communication units near the radiating transmission line will be transmitted and received from the base station. The communication system is particularly suited for use in underground mines in which event the base station can be located at the surface, and the mobile communication units are generally located in the mine shafts.

Abstract: A waveguide antenna (1) has an upper (2) and air (3) cavity waveguide, these waveguides being separated by a partition wall (4). Transversely extending slots (7) are disposed along the center line of the upper waveguide (2) with a mutual spacing of one wavelength-distance (.lambda..sub.g). Two slots (6) which extend in the direction of the longitudinal axis of the waveguide are disposed between the transversal slots (7). The partition wall (4) is provided with longitudinally extending slots (8) immediately beneath the longitudinally extending slots (6), and field-shifting posts (9) are placed in the lower waveguide (3) adjacent the latter slots (8) in a zig-zag pattern along the waveguide (3). Baffles (10) counteract grating lobes. A fundamental mode of an electromagnetic field (E1) in the upper waveguide (2) excites only the transversal slots (7), which radiate a field (E3). The same fundamental mode (E2) in the lower waveguide (3) excites the slots (8) in the partition wall.

Abstract: In an intrusion detection system comprising an open transmission line (10), for example a "leaky cable", and a receiver unit (12S,12T,14S,14T,16) for processing a radio frequency signal received by the line to detect perturbations caused by an intruder (28), problems of nonlinear sensitivity due to line attenuation are resolved by combining perturbation signals (R.sub.S, R.sub.T) from both ends of the open transmission line. A processor unit (18) computes logarithmic values of the perturbation signals from the opposite ends of the line and combines them to detect presence of an intruder. The sum of the logarithmic values may be used to determine presence of the intruder and the difference between them may be used to determine the location of the intruder relative to the end of the line. The processor may also use phase information from the two perturbation signals to facilitate detection in the presence of multipath effects. Reference signals (LO,IF.sub.

Abstract: A cable for use as a distributed antenna in intrusion detection systems comprises an internal open transmission line in parallel with a periodically loaded structure which supports an external transmission line mode of operation, specifically a surface wave, and is "driven" by the open transmission line. The periodically loaded structure may comprise transmission line segments for example cylindrical conductor elements intercoupled by serial inductive coupling. There are no fewer than three and no more than fifteen conductor elements in one wavelength (.lambda..sub.S) of the external transmission line modes. Preferably the length of each transmission line segment is about one quarter of the wavelength (.lambda..sub.S) of the external transmission line modes. The inductive coupling may be provided by resistance wires extending alongside the conductor elements.

Abstract: In a radiating high-frequency coaxial cable with openings in the outside conductor (6), which are essentially slots (7) cut perpendicular to the cable axis, sections with periodically repeating slot configurations are provided along the cable, which differ in period length with a constant number of slots per period length, and/or differ in the number of slots per period length while the period length remains constant.

Abstract: A communication system that utilises leaky feeder cables (1) has a ruggedised tubular housing (8). The housing is preferably made of stainless steel, and to enable ingress and egress of signals the housing is provided with discontinuities. The discontinuities are preferably arranged to establish a regular pattern on the signals.

Abstract: An improved microstrip patch antenna has a pair, for example, of dielectric overlay strips attached along the radiating edges of the patch where the patch is rectangular. By optimizing dimensions parameters and materials, the bandwidth of the patch is increased substantially as well as the amount of radiated energy.

Abstract: A radiating air-dielectric coaxial cable for plenum applications comprises an inner conductor; a non-halogenated dielectric spacer around the inner conductor; and a single, continuous, outer conductor surrounding the dielectric spacer in direct contact therewith. The outer conductor has apertures along its length for the passage of electromagnetic radiation. At least one layer of inert, flame-retardant barrier tape is wrapped over the outer surface of the outer conductor so as to cover each of the radiating apertures of said outer conductor to prevent the dielectric spacer from flowing out through the radiating apertures when the dielectric material is melted. A jacket of halogenated, highly flame-retardant polymer is extruded over the wrapped layer of barrier tape.

Abstract: Dielectric strips made of a dielectric material are placed between a pair of conductor plates located a specified distance apart. Cutouts are formed in the dielectric strips. The cutouts, a part of each dielectric strip is formed into an electrically asymmetric portion. When high-frequency power is supplied to the dielectric strips, the power is transmitted through an NRD waveguide composed of the dielectric strips and the pair of conductor plates, with the result that electromagnetic wave is radiated from the cutouts into the space between the conductor plates. This electromagnetic wave excites the radiation elements formed in the conductor plates, which then radiate electromagnetic waves.

Abstract: A dielectric material is formed into a structure having two parallel broad surfaces with one or more raised integral portions extending transversely across at least one of the broad surfaces. The exterior is uniformly conductively coated resulting in a parallel plate waveguide having a continuous transverse stub element disposed adjacent one plate thereof. Purely reactive elements are formed by leaving the conductive coating on the terminus of the stub element, or by narrowing the terminus of the stub element. Radiating elements are formed when stub elements of moderate height are opened to free space. Radiating, coupling and/or reactive continuous transverse stub elements may be combined in a common paralled plate structure in order to from a variety of microwave, millimeter wave and quasi-optical components including integrated filters, couplers and antenna arrays.

Abstract: A radiating cable comprises a core having a center conductor bonded to, centered in, and supported by discs of dielectric material. A sleeve of dielectric material is extruded over the discs and thereby bonded thereto to form a plurality of sealed, coaxial, dielectric chambers. A tubular outer conductor is bonded in concentric relation to the sleeve. In a continuous process, at least one slot is formed in the outer conductor by a cutting operation and an outer jacket is extruded over the outer conductor. In a preferred embodiment, the outer conductor is made of an aluminum tube and two circumferentially equally spaced slots are formed therein by removing between 10 and 35% of the aluminum material. The width of the resulting slots may be configured so that a joint is formed in the slot between the insulating sleeve and the outer jacket, thus obviating the use of adhesive in bonding the outer jacket to the cable.

Abstract: The present invention concerns a high frequency radiating line for radiating electromagnetic energy in a frequency band and comprising at least one tubular conductor (23) surrounding a longitudinal axis (X) and having a plurality of apertures formed into a series of identical patterns (M1) repeated periodically with a period P along said line, characterized in that, when the operating frequency band is of the type [f.sub.r,(N+1)f.sub.r ], where f.sub.r is a given frequency and N is a positive integer greater than 1, each of said patterns (M1) comprises N apertures 0 to N-1 and satisfying the following equations: ##EQU1## where: the index k is an integer such that 1.ltoreq.k.ltoreq.N-1 and refers to the k'th aperture of one of said patterns (M1),z.sub.k is the distance between said k'th aperture and first aperture (F0) of the pattern,a.sub.k is the polariability of the k'th aperture,a.sub.o is the polarizability of the first aperture, ##EQU2## where E(x) designates the integer part of x, p.sub.

Abstract: A communication system serving a plurality of radio units in a frequency blocked area includes a remotely controlled and remotely configurable network of radiating coaxial conductors. The radiating coaxial conductors, along with associated amplification devices, are arranged to provide radio communication to an area around the network using radio frequency radiation released by the plurality of radiating cables. Remote control to the system is provided by a control station which transmits control data to the amplification devices through the network of radiating coaxial conductors. The amplification devices are arranged to control the radiating coaxial conductors in such a way that, in response to receiving the control data, the radiating coaxial conductors may be reconfigured to overcome faults occurring in the system.

Abstract: In a high frequency radiation cable, with groups of openings arranged periodically in the outside conductor of a coaxial cable, the number of openings per periodic length increases in sections along the cable, where the sections are whole number multiples of the periodic length.

Abstract: A dual leaky coaxial cable comprising a pair of parallel elongated conductors, a dielectric surrounding each of the conductors, separate first external conductive shield apparatus surrounding at least the major portion of each of the dielectrics, separate second external shield apparatus surrounding each of the first external shield apparatus, apparatus associated with the shield apparatus for selectively coupling magnetic fields which may surround each of the elongated conductors through the first and second surrounding external shield apparatus, and apparatus for maintaining the individual respective second external shield apparatus separated by a distance which is a fraction of the diameter of either of the second external shield apparatus.

Abstract: A communication system for transmitting data between a transmitting platform and a receiving platform, having two equal lengths of leaky coaxial cable forming the transmitting antenna which is located on the transmitting platform and the receive antenna is located on the receiving platform. The two equal lengths of leaky coaxial cable form a circle wherein one end of each of the equal lengths is a feedpoint for inputting data and the other end of each of the two equal lengths is terminated with a resistor to ground. The receive antenna is maintained a predetermined distance from the plane of the transmitting antenna.

Abstract: A leaky cable useful antenna or as an intruder detector sensor either buried in a single trench or above ground substantially reducing sensitivity variations due to the environment. Egression of the electric field from the cable is blocked but magnetic fields escape. The velocity of the externally propagating electromagnetic field is slowed and attenuated. In one embodiment, the leaky coaxial cable is comprised of an inner conductor, a dielectric surrounding the inner conductor, a first external shield having low series impedance at VHF frequencies surrounding the dielectric, means for coupling a magnetic field through the first external shield, a second external shield surrounding the first external shield having high series impedance relative to series impedance of the first external shield and means for limiting VHF conduction current between the shields, which effectively causes separation of the internal and external propagation fields of the cables.

Abstract: Waveguide apparatus in which a dielectric substrate is placed between sections of a waveguide. The dielectric substrate incorporates slots arranged in a linear fashion and having extended portions, there being a narrow gap between adjacent slots. This enables accurate control of radiation losses through the dielectric layer sandwiched between the sections of the waveguide to be achieved.

Abstract: An intrusion detection system of the type using cables arranged along a perimeter to be protected and sensing changes in the electrical field around the cables caused by the presence of an intruder. The cables are divided into sections or blocks and typically only one of the sections is energized at any time. The variations caused by an intruder at the selected sections are transmitted through the intervening section to the receiver portion of a transceiver located at one end of the cables. This indicates in which section intrusion has occurred. The system uses continuous wave excitation whereby the expense and complexity of high speed switching and timing of r.f. signals are avoided.

Abstract: A radiating cable of the foam dielectric type is provided with increased flame-retardant capabilities by provision of an inert barrier tape between an apertured, corrugated outer conductor and the external jacket surrounding the conductor. The barrier tape is composed of non-halogenated, self-extinguishing insulating material and is wrapped over the outer conductor in such a way as to completely cover the radiating apertures disposed thereupon. The barrier tape prevents the melting and bubbling of the dielectric foam outwardly through the radiating slots into penetrating contact with the external jacket when the cable is subjected to high-intensity flames, without significantly affecting the transmission characteristics of the cable.

Abstract: A fire resistant refractory leakage coaxial cable assembly formed by placing a sheet of heat resistant organic film between the internal conductor and the external conductor of a leakage coaxial cable. The seam formed by the two edges of the film is positioned upwardly, so that molten insulated material will be contained by the film without flowing through the seam.

Abstract: A leaky coaxial cable is designed to produce a defined coupling between its interior and exterior. A bonded and insulated outer conductor of relatively large width relative to the cable diameter, is spirally wound at a low pitch angle to provide at high frequencies a coupling level having minimal effect on the coaxial properties of the cable.

Abstract: A microwave heating applicator usable in preformed holes in mansonry and the like for heating and dehumidifying areas around the holes is formed from a length of coaxial transmission line. Radiating elements are formed in the outer conductor of the coaxial line for providing an asymmetrical radiation pattern. The radiating elements are provided by forming circumferential axial discontinuities in the outer conductor, each discontinunity having a pair of non-parallel cut edges formed in the outer conductor encircling the line, leaving an asymmetrical open area extending axially between the cut edges. One of the cut edges may describe a plane perpendicular to the coaxial line's z axis while the other cut edge describes a plane which is not perpendicular to the coaxial line z axis. The radiating elements may be provided at intervals along the coaxial line.