Abstract: A system with two concentric antennas for two bands of microwave frequencies includes between the two concentric antennas a system for eliminating or attenuating propagation of waves from the inner antenna to the outer antenna.

Abstract: The microstrip antenna of the present invention has a basic structure of a ground conductor plate, dielectric substrate and radiation conductor plate laminated together. On the dielectric substrate, upon which the radiation conductor plate is formed, two radio wave reflectors are placed parallel to each other facing across the radiation conductor plate. The two surfaces of the two radio wave reflectors that are facing each other are either perpendicular to the dielectric substrate, or else the interval between the two surfaces enlarges as they depart from the dielectric substrate. Due to this structure, by increasing the variation in antenna directivity, the antenna can be made less susceptible to noise generated from noise sources in the antenna vicinity. Moreover, the antenna can be small-sized since the radio wave reflectors can be placed close to the radiation conductor plate.

Abstract: An antenna system comprises at least two dipole antennas (6) constituting an antenna module and is placed above and parallel with a common, artificial ground plane (5) in the form of an electrically conducting plate, for instance the bottom of a metal box (2). The dipoles (7) and the feed lines (8, 9, 10, 11) are designed as air dielectric strip-lines and are configured in one piece of a homogeneous material and extend mechanically and electrically in an uninterrupted manner from the dipoles to the antenna connector. The parts configured in one piece are produced by punching out sheet metal, and after suitable bending the parts are inserted in corresponding openings (16) in the ground plane (5).

Abstract: An active receiving antenna for vehicles, including a slot-shaped antenna cut into the metallic vehicle body, and having small-depth cavity filled with a dielectric material which closes off the antenna toward the back or interior of the vehicle. A low-noise preamplifier, which is integrated into the dielectric material, is connected to the antenna via two feed lines of different length. The desired polarizations of the received signals are set via this preamplifier, which can be changed over and be switched off.

Abstract: A dual frequency feed element for a parabolic reflector antenna system, comprising a conductive cavity having a central axis, the cavity mounted at the focal point of a parabolic reflector surface and defined about its outer perimeter by an upstanding cavity wall, and having a closed cavity floor and an open top directed toward the reflective surface, a dual frequency radiating element centrally disposed in the cavity and arranged to radiate a first low frequency signal out through the cavity open top to the antenna surface, a conductive floor fixed below the radiating element a distance in relation to the radiant energy for the first low frequency signal, and disposed in the cavity transverse to the central axis thereof to reflect radiant energy for the first signal and, a frequency selective surface fixed below the radiating element, apart from the conductive floor, and transverse to the central axis of the cavity to reflect radiant energy for the second, higher frequency signal while simultaneously being i

Abstract: A repeater station having circularly polarized antennas. A diamond panel antenna and a panel antenna are positioned in a back-to-back relationship. Each antenna is circularly polarized. The antennas use "tunnel technology" for isolating the antennas. A chassis forming a recessed portion is provided. A dielectric board is inserted into the recess. Patch elements mounted on a board are inserted into the recess and connected to the dielectric board. The width of the boards are such that a "tunnel" is formed about the periphery thereof. Absorber material is then inserted into the tunnel around the boards. A radome is placed over the recess enclosing the boards and elements.

Abstract: An array antenna (12atf) particularly useful for a spacecraft includes a plurality of antenna elements (310). Each of the elements includes a conductive hexagonal cup (408) having sides (410a, 410b, 410c, . . .) which are thirteen twentieths of a wavelength long at the center frequency, and have a height above the bottom (412) which is a little more than one-third wavelength. A crossed dipole (420) includes two dipoles (420V, 420H), the first (421, 422) having elements approximately one quarter wavelength long, and the second (420H) having elements (423, 424) about three twentieths of a wavelength long. The plane of the crossed dipole is about one quarter wavelength above the bottom of the cup. A first director ring (512) has a diameter of about one quarter wavelength, and is spaced about nine tenths of a wavelength above the bottom. A second director ring (514) has a like diameter, and is spaced about seven tenths of a wavelength above the bottom of the cup.

Abstract: An integrated directional antenna includes a radome, a resonant cavity within the radome, a microstrip radiator and a patch re-radiator positioned within the resonant cavity to provide a directed or focused beam. A first radiator can be provided for signal transmission and a second radiator for signal reception. A chassis member is located within the radome and defines the resonant cavity/ies and a rear cavity for electronic components. A rear cover can incorporate an integral heat sink for dissipating heat from electronic components within the rear cavity. An antenna mounting bracket has first and second spaced mounting points to allow a large range of mounting angles with a compact construction. The chassis member, the radio transmission and/or receiving elements and the electronic circuit elements can be sandwiched together in a desired configuration by fixing the rear cover to the radome. The antenna finds particular application in the field of radio telephony systems.

Abstract: A circularly polarized antenna has an open reflector box, an array of crossed dipoles, and a single binary feed network. The open reflector box is formed of conductive material, has a ground plate and four side walls defining an opening, and has an input port for receiving an input signal. The single binary feed network is disposed within the open reflector box, is connected to the input port, and has a microstrip transmission line spaced from the ground plate. The microstrip transmission line has conductive bars mounted parallel to the ground plate and spaced therefrom forming an air dielectric low loss microstrip. Each pair of crossed dipoles has a first dipole comprising two downwardly bent radiating elements arranged at an angle with respect to the ground plate, and has a second dipole comprising two straight radiating elements arranged parallel to the ground plate.

Abstract: An antenna/downconverter directed to the subscription television distribution industry having low cross polarization and broad bandwidth. The antenna/downconverter includes a director mounted to a housing which defines a reflector cup, side lobe suppression rim and a housing defining a chamber which provides environmental protection for downconverter electronics. Received microwave energy is coupled to the downconverter electronics from a point radially inward from the perimeter of a first receive disc axially spaced within the reflector cup using a probe surrounded by a conductive probe shield integral to the reflector cup. A second receive disc having a different radius than the first receive disc and axially spaced within the reflector cup is parasitically coupled to the first probe. The second receive disc additionally includes wings coupled to the perimeter of the reflector cup for shunting cross-polarized microwave signals.

Abstract: Improved antennas and antenna systems for use in cellular and other wireless communications systems. A folded mono-bow antenna element is provided which has a substantially omnidirectional radiation pattern in a horizontal plane and shows variation in gain in an elevation plane depending upon the size of an associated ground plane. The folded mono-bow antenna element comprises a main bowtie radiating element and parasitic element wherein the main bowtie radiating element and parasitic element are separated by a dielectric material having a dielectric constant preferably less than 4.5 and, in some cases, less than or equal to 3.3. Various antenna arrays and methods of making the same are also provided.

Abstract: A low profile, compact microstrip-to-waveguide or stripline-to-waveguide transition. The end of the waveguide is terminated in a cavity backed slot defined in a groundplane formed on a dielectric substrate. The slot is excited by a microstrip or stripline conductor defined on the opposite side of the substrate. The conductor is terminated in a T-shaped junction including two opposed arms extending along the slot, each having a length equal to one-quarter wavelength at the center frequency of operation. A cavity covers the substrate on the conductor side, and is sized so that no cavity modes resonate in the frequency band of operation. The transition is matched by appropriate selection of the length of the slot and the length and position of the microstrip.

Abstract: A low profile, compact microstrip-to-waveguide transition which utilizes electromagnetic coupling instead of direct coupling. The end of the waveguide is terminated in a cavity backed slot defined in a groundplane formed on a dielectric substrate. The slot is excited by a microstrip line defined on the opposite side of the substrate, offset from the slot centerline. A cavity covers the substrate on the microstrip side, and is sized so that no cavity modes resonate in the frequency band of operation. The transition is matched by appropriate selection of the length of the slot and the length and position of the microstrip.

Abstract: A flip-chip integrated circuit having passive 302, 304, 306 as well as active 308, 310 components on a frontside surface of a substrate. The active device have airbridges which contact a heatsink to provide heat dissipation from the junctions of the devices.

Abstract: An antenna (10) is provided by a metal layer (12) deposited on a dielectric substrate (16) which is etched to form a pair of symmetrical slot sections (20,22) having facing edges which increasingly curve away from each other to a maximum spacing point which is the antenna aperture (26). A linking slot (32) interconnects the slot sections (20,22) at a feed point (30) spaced from the aperture (26). High frequency electrical voltage applied at the feed point (30) achieves launch of an electromagnetic wave from the aperture (26). An alternative feed network uses a 180.degree. hybrid (60) providing simultaneous horizontal and vertical polarization operation.

Abstract: A telecommunication system antenna including: a non-resonating three-wire type folded element which generates an unbalanced mode current and has a matching function; a sleeve element which consists of a conductive sleeve with its one end near the non-resonating three-wire type folded element and a conductive disk in a flange shape around the circumference of the other end of the conductive sleeve, so that the sleeve element radiates electromagnetic waves based on the unbalanced mode current generated by the non-resonating three-wire type folded element; and a coaxial line with its tip end inserted into the conductive sleeve of the sleeve element from the other end of the conductive sleeve so that the coaxial line is electrically connected to the conductive sleeve and to the non-resonating three-wire type folded element.

Abstract: A nested cup dipole feed capable of collinear polarization for all bands, and frequency staggering of one linear polarization with respect to the orthogonal linear polarization. The dipole elements for all bands are collinearly placed, making one linearly polarized set to be orthogonal to the other collinear sets. One collinearly placed dipole can be tuned differently from the orthogonal ones to permit frequency staggering at the crossover frequencies, thus permitting at least high gain for one polarization.

Abstract: A broad band mobile telephone antenna comprises a first conductive circular plate and a second conductive circular plate. The first plate is located above and in parallel with the second plate. The diameter of the second plate is equal to or larger than that of the first plate. The second plate is used as a ground plate, is attached on a body of an automobile. A short-circuit rod, for matching an impedance between the first plate used as an antenna and a coaxial feeder cable for the antenna, is connected between the first and second plates. An upper end of a core rod is connected to the first plate at the substantial center thereof. A lower end of the core rod is extended toward an opening formed in the substantial center of the second plate. The opening is connected to a connector which is placed inside the automobile through an opening formed in the body. The connector connects the core rod and the coaxial cable which is connected to a transmitter/receiver of a mobile telephone system.

Abstract: A method and apparatus is provided for measurement-while-drilling utilizing improved antennas. An elongated tubular member is provided with an outer peripheral surface having a contoured portion defining a plurality of discrete communication regions of reduced radial dimension. An antenna pathway is defined in the elongated member substantially transverse to the plurality of discrete communication regions. An antenna member is partially disposed in the antenna pathway with portions of the antenna member extending out of the elongated member at the plurality of discrete communication regions to facilitate communication of electromagnetic energy. In a reception mode of operation, the antenna member detects electromagnetic energy in the wellbore and generates a current corresponding thereto. If operated in a transmission mode of operation, the antenna member emits electromagnetic energy in the wellbore in response to an energizing current.

Abstract: A phased antenna array which includes a single piece electrically conductive faceplate which uses accurately positioned posts with precision formed grooves in the post faces to obtain accurate board placement of the boards relative to each other. The element boards penetrate through slots in the bottom portion of the faceplate and rest in the precision formed grooves in the posts at opposing sides of a slot with the board edges restrained by the grooves in the posts. The portions of each element board extending out of the slots are accurately positioned by providing holes in each of the element boards through which pins are positioned to accurately determine the amount of entry of the elements into the slots. As an alternative, some or all of the element boards can be secured to an external structure which does not move relative to the faceplate to accurately position the boards relative to the faceplate.

Abstract: A circularly polarized microcell antenna 10 that requires only a single feed-line to radiate circularly polarized electromagnetic energy therefrom. The antenna 10 comprises a reflector box 14 having a bottom 15 and side walls 17 to which an electrical connector 20 is mounted. The center conductor 24 of the connector 20 is electrically connected to a conductor bar 22 upon which a first dipole assembly is mounted at a designated one-quarter wavelength location. The shell of the connector 20 is electrically connected to the reflector box 14 upon which a second dipole assembly is mounted at a designated one-quarter wavelength location. Each dipole assembly comprises a primary dipole arm 52 and a secondary dipole arm 68 which are electrically connected by a phasing loop that introduces a 90.degree. phase shift between the primary dipole arm 52 and the secondary dipole arm 68.

Abstract: A microstrip antenna device having a dielectric layer, a conductive patch of a chosen shape on one side of the layer and, on the other side of the layer, a conductive plate forming a ground plane; and, a feed circuit comprising at least one microstrip line connected to the conductive patch and implanted in the dielectric layer in the same plane as the conductive patch. The thickness of the dielectric layer opposite the microstrip line is greater than the thickness opposite the periphery of the microstrip line. Further, the thickness of the dielectric layer opposite the conductive patch is greater than the thickness opposite the microstrip line, and also greater than the thickness opposite the periphery of the conductive patch.

Abstract: A radiating device for a planar antenna, said device including a first ground plane and a second ground plane, a slot (25) provided in the first ground plane and being fed by electromagnetic coupling from a feed line (17), and an assembly of a plurality of thin conductive parts; the central portion of the radiating slot (25) being a conductive part (15) supported at its center by a supporting column (18). Application in particular to the space field.

Abstract: The invention relates to a dielectric resonator antenna system which exhibits an unusually wide bandwidth. This is achieved by chosing a patch antenna/dielectric resonator combination with shape and dimensions such that resonance modes over a continuous range wavelengths can be established therein. The bandwidth and transmission properties of the device are further improved by including a dielectric coupling element (between the dielectric resonator and air) whose antireflection characteristics are optimized for a wavelength which is slightly different from the maximum wavelength of the patch antenna.

Abstract: A spiral antenna is provided which is capable of providing dual circular polarization operation with a large number of operating modes. The spiral antenna includes at least eight conductive spiral antenna arms extending outward about an axis of rotation. Each antenna arm has an inner end and an outer extending end and a plurality of arm width modulations formed therebetween for achieving dual circular polarization operation capability. Electrical feeds are coupled to the inner end of each of the spiral antenna arms. A feed network may be further connected to the electrical feeds for providing predetermined phase excitations to the corresponding spiral antenna arms so as to achieve the desired operating modes.

Abstract: The invention concerns a broadband antenna element for array antennas using microstrip technology. In accordance with the invention, an etched patch 2 on a dielectric substrate 1 is disposed at the bottom of a cavity 7 defined by conductive walls 8, cylindrical walls, for example, or walls of more complicated geometry. Depending on the embodiment, the conductive walls 8 can extend through the dielectric substrate 1 to form an electric contact with the ground plane 6 or a second resonator comprising a second etched patch 12 on a second thin dielectric substrate 11 may be placed in front of the cavity 7. The invention also applies to antenna subarrays constructed from a plurality of these antenna elements and to array antennas constructed from a plurality of these subarrays.

Abstract: A slot fed antenna is disclosed for use in radiating energy. The antenna includes a flat conductive member having an elongated vertically-oriented slot dividing the member into a pair of horizontally-extending variable-length flat dipole wing elements. Each of the flat dipole wing elements has a vertically-extending rectilinear edge. Also, each wing element extends in width in a direction perpendicular to the rectilinear edge from a minimum at its center and at each of its upper and lower ends to a maximum midway between each of the ends and the center.

Abstract: Monolithic microwave integrated circuit (MMIC) technology is advantageously used to fabricate microwave circuitry for an antenna-converter system to enable an antenna and its associated converter circuits to be integrated together into a unitary package. Small reliable radio frequency (RF) circuits, polarization switch matrix circuits, intermediate frequency (IF) circuits and power and control circuits for the converter are manufactured and integrated onto a plurality of small area microwave circuit disks using MIC/MMIC technology. The plurality of converter circuit disks are sandwiched together and directly mounted flat against the back of the antenna to form a unitary package. The disks for the converter circuits are further sized such that the circuit disks fit within an envelope volume defined by the size and shape of the antenna.

Abstract: A broadband antenna array, formed of pairs of horizontally-spaced dipoles that are balun-fed, uses an air dielectric microstrip binary-feed network to optimize antenna bandwidth. Each dipole is fed by a three-wire balun which maintains the proper current distribution on the dipoles over the operating bandwidth. The binary-feed network feeds each dipole individually to further optimize the antenna's pattern bandwidth. The binary-feed network is formed using a conductive ground plane with spaced conductors to utilize an air dielectric, thereby minimizing antenna losses in the feed network. The feed network impedances are chosen to give a broadband impedance match to the dipoles, and the entire assembly of binary-feed network and dipoles is mounted in a reflector box, the dimensions of which are chosen to control the antenna beamwidth. Vertically stacked pairs are used to compress the vertical radiation pattern for greater antenna gain.

Abstract: A base station for a mobile communications system including an antenna for transmitting a radio carrier wave to a mobile communications device and receiving signals therefrom, a coaxial external conductor including a skirt in the form of a sun shade having a length equal to a quarter wavelength of the radio carrier wave, a radio section located inside the coaxial external conductor for providing radio communication with the mobile communication device via the antenna, and a connecting section connecting the radio section to a telephone line and where the antenna is configured in the form of an upper disk of a discone antenna and where the skirt is a lower conical member of the discone antenna.

Abstract: A microwave antenna element suitable for constituting one of the elements of an array, the antenna element being capable of transmitting or receiving two orthogonally-polarized microwaves. The antenna element is constituted by a cavity containing two orthogonal excitation probes separated by a polarization-selective obstacle forming both a short-circuit plane for the microwave transmitted by the top probe, and also a patch for the microwave transmitted by the bottom probe. Another patch is common to both of the interlaced antennas. A third patch which is polarization-selective in the sense that it is transparent for the microwave transmitted by the bottom probe, may also be provided.

Abstract: A cavity with a plurality of notches formed in the edge of the open end. Each notch is fed to establish a notch-type antenna. Notches at 90 angles from each other are formed for a monopulse application. A coaxial feed line is used where the outer conductor is connected at one side of the notch and the inner conductor at the other side. The sizes of the cavity and notches are selected to radiate energy of a selected frequency bandwidth. Additional cavities of different sizes for radiating different selected frequencies are nested concentrically together to form a multifrequency antenna array with a common phase center. Each cavity has a plurality of notches and each cavity may be rotated in relation to the adjacent cavity to misalign the notches between the two cavities and thereby increase isolation between frequency bands.

Abstract: A system and method for "power beaming" energy from a source at high frequencies and rectifying such energy to provide a source of DC energy is disclosed. The system operates at a frequency of at least 10 GHz and incorporates a rectenna array having a plurality of rectenna structures that utilize circuit elements formed with microstrip circuit techniques. Each rectenna element is associated with a resonating cavity structure.

Abstract: A generally planar antenna structure having at least six radial antenna elements, each of which uses log-periodic principles to provide a broad bandwidth of operation. Each antenna element has a radial arm and integral, arcuate teeth extending in opposite directions from the radial arm, such that the spacing, width and length of the teeth increases with increasing radial distance from the center of the structure. The teeth are preferably interleaved with teeth in adjacent antenna elements. A feed region of the structure is provided near its center, to connect the antenna elements through a connection matrix to input/output terminals and provide operation in multiple modes and multiple polarization senses.

Abstract: A freqency selective surface for passing electromagnetic wave energy and the selected frequency band is described. The device includes a conductive apertured substrate having apertures formed therein which are sized and arranged in a predetermined patern. The apertures each form a waveguide segment for electromagnetic energy. In one embodiment dielectric loading material is moldably formed directly into the apertures. In a bipolar arrangement, conductive patches are located on opposite sides of the dielectric coaxially with each waveguide for establishing a capacitive load in accordance with the area of the patches. Dielectric matching material on opposite surfaces of the substrate is employed to match the surface with external media for efficient electromagnetic wave propagation. Other arrangements employ notched patches and air dielectrics.

Abstract: Radomes having increased transparency and reduced reflectivity and refractivity to radar waves may be prepared or repaired utilizing heat-curable resin-containing structural materials in which the heat-curable resin contains greater than about 70 weight percent of cyanate functional monomers. The structural materials take the form of matrix resin impregnated prepegs and composites, film adhesives, paste adhesives, syntactic foams, and expandable foams, and may be used to prepare numerous useful structural features including honeycomb materials and leading edge radomes containing syntactic foams. The heat-curable resins further facilitate the preparation of low observable structures.

Abstract: A method and apparatus measures dielectric properties over a broad range of frequencies. The functions of various resistivity and dielectric constant measuring devices such as logging tools are combined in a single tool. A measuring tool includes novel transmitting and receiving antennas. Electromagnetic energy flows to a transmitting antenna. A stripline adapter permits transmission to a stripline having a metallic central strip. A strip face is bent at approximately right angles, and has a length that is compatible with the desired frequency coverage. A ground plane extends from the stripline adapter to the right angle bend, and a void exists between the center strip and the ground plane. A dielectric is positioned to nearly fill the void. The antennas are positioned so that the strip face lies flush with the tool face, to permit electromagnetic energy to be transmitted into and out of the material to be analyzed.

Abstract: An antenna capable of being mounted flush with variously shaped surfaces. The antenna comprises a dielectric filled radiating cavity with two opposing tapered walls. The radiating cavity is excited by a microstrip horn.

Abstract: A planar antenna of the kind comprising feed lines disposed in a flat circuit and cooperating by hyperfrequency coupling with a metal ground plane plate pierced by apertures has the feed lines presenting a termination juxtaposed with each aperture. A lower ground plane plate is disposed at a distance of approximately a quarter wavelength from the apertured metal plate. The apertured metal plate comprises a metal coating deposited on a dielectric substrate. The feed line comprise central conductors disposed in channels which open into the apertures. The array of apertures, channels and conductors can be produced on the dielectric substate by single face printed circuit techniques. The antenna may be used for the reception of direct broadcasts from satellites.

Abstract: A method of placing an electronic responder of an electromagnetic interrogation system or an antenna coil of an electromagnetic interrogator device in or near an electrically conductive article. An opening is made in the article, which is larger than the responder or antenna coil, and the responder or the antenna coil is mounted in registry with said opening. There is also provided a slit in the article, extending from the opening, said slit interrupting extraneous circular currents.

Abstract: The I.F.F. sum and difference channels are obtained by means of the reflector of the radar, illuminated by primary radiating elements associated with the horn of the primary source of the radar. Furthermore, the signals of the I.F.F. sum and difference channels are suitably mixed to obtain a reduction in the level of the cross-polarized signals.

Abstract: A cavity-backed dual-slot antenna element for circular polarization having a single probe extending from the end of the feed line for the element and arranged to couple energy into the resonant slots. The probe lies in the plane of the feed line and has the form of an open circle having a circumference of approximately one wavelength at the operative frequency. The probe is constrained to lie within the boundary of the resonant slots as projected onto the plane of the feed line. The arrangement produces a circular polarization having a greater axial-ratio bandwidth than that of conventional antennas using two orthogonal probes or using a single probe feeding a resonant patch. An antenna comprising a flat array of the elements is suitable for use in DBS (Direct Broadcast by Satellite) TV reception. However, the probe itself is not limited to use in slot antennas and it has applications in other antennas or couplers for circular polarization.

Abstract: A device for exciting a waveguide with circular polarization from a plane antenna, said waveguide (10) being a rectilinear hollow waveguide closed at one of its ends (12), said antenna being excited by at least two coaxial ports (13, 14) fed in phase quadrature by a circuit including a hybrid coupler (15), and being constituted by a radiating plane metal pattern (11) disposed on the surface of an insulating substrate (18) closing the waveguide (10) perpendicularly to its axis of symmetry.

Abstract: A triplate fed slot antenna in which a conductive sheet has a slot with a length of .lambda., where .lambda. is the wavelength of a signal intended to be radiated from or received by the antenna. A triplate feed structure is coupled for feeding the slot. The triplate feed structure includes two outer conductors defining walls of a resonant cavity backing the slot, and an inner conductor disposed in the cavity.

Abstract: Radomes having increased transparency and reduced reflectivity and refractivity to radar waves may be prepared or repaired utilizing heat-curable resin-containing structural materials in which the heat-curable resin contains greater than about 70 weight percent of cyanate functional monomers. The structural materials take the form of matrix resin impregnated prepegs and composites, film adhesives, paste adhesives, syntactic foams, and expandable foams, and may be used to prepare numerous useful structural features including honeycomb materials and leading edge radomes containing syntactic foams.

Abstract: An antenna includes an array of electrically conductive cells each having one open side and containing a radiating/receiving element. The conductive cells reduce mutual coupling between elements.

Abstract: An antenna has a resonant cavity defined by electrically conducting plates and a sidewall, and has sixteen helical antenna elements each with five turns in the helical section and a probe at the opposite end, the stem of probe passing through an aperture in upper plate so that its end is within the resonant cavity common to all elements in that module.The cavity has a cross-section parallel to the plates essentially square in shape except for the presence of four inwardly-protruding buttresses, one situated mid-way along each side of the cavity to promote the formation of standing waves of different mode, and thereby enhance the frequency range of the array.

Abstract: The described embodiments of the present invention provide a high-gain antenna while allowing for the inclusion of devices within the antenna array. In one embodiment of the invention an array of receiver/transmitter elements is positioned in a pan-like reflector base. The elements are positioned one-quarter of a wavelength from the surface of the base. The wavelength is the wavelength of the chosen frequency of transmission or reception of the antenna. A partially reflective plate is positioned one-half wavelength from the base and thus one quarter wavelength from the elements. Reflective disks are also positioned one-half wavelength above the base and are positioned directly above the elements. The disks create a resonant cavity around the elements for waves of the chosen frequency arriving from near normal to the plane of the base or being emanated from the elements at a normal or near-normal angle. The partially reflective plate extends this resonant area spatially from the element.

Abstract: An antenna which conforms to the surface of a spacecraft can be a thin slot antenna which can be formed to the shape of the craft in combination with a compact ground plane formed of T-shaped or L-shaped pieces.

Abstract: A supersonic aircraft or missile broad bandwidth antenna is provided. This antenna is constructed into a cavity created in the fuselage or wing of the aircraft and covered with a radome for flush mounting. The cavity comprises side walls and a bottom constructed of electrically conductive materials which are caused to be electrically excited by an antenna element located within the cavity. This antenna element, which is capable of broad bandwidth operation, is either passively or actively tuned. Active tuning is carried out by a logic converter circuit connected to the antenna from a communications transceiver.