Abstract: An integrated circuit antenna structure for transmitting or receiving millimeter and/or submillimeter wave radiation having an antenna relatively unimpaired by the antenna mounting arrangment is disclosed herein. The antenna structure of the present invention includes a horn disposed on a substrate for focusing electromagnetic energy with respect to an antenna. The antenna is suspended relative to the horn to receive or transmit the electromagnetic energy focused thereby.

Abstract: A compact, easy to manufacture quarter-wavelength microstrip element especially suited for use as a mobile radio antenna has performance which is equal to or better than conventional quarter wavelength whip-type mobile radio antennas. The antenna is not visible to a passerby observer when installed, since it is literally part of the vehicle. The microstrip radiating element is conformal to a passenger vehicle, and may, for example, be mounted under a plastic roof between the roof and the headliner.

Abstract: A printed circuit array antenna includes at least one printed circuit formed by a substrate having radiating elements on a first face and an energy distribution tree on a second face. The array antenna is provided with a front structure having an elongated shape and superposed on the first face of the printed circuit. The front structure is composed of a substrate pierced with radiating apertures located opposite to the radiating elements of the printed circuit.

Abstract: A central aperture provides at least two radiation pattern modes. A second aperture concentric with the central aperture provides at least two radiation pattern modes. A first feed system excites the central aperture and a second feed system excites the concentric aperture. Circuit means associated with the second feed system provides an auxiliary excitation to the concentric aperture which results in optimizing the radiation pattern obtained during excitation of the central aperture.

Abstract: A polarized signal receiver waveguide assembly, or feedhorn, for receiving a selected one of linearly polarized electromagnetic signals in one waveguide of circular cross-section and for launching or transmitting the selected signal into a second waveguide, the axes of the waveguides being disposed at right angle. The first waveguide has a closed end wall, formed as a hemispherical cavity having a hemispherical concave surface. A probe comprising a signal receiver portion disposed in a plane perpendicular to the axis of the first waveguide and a launch or re-transmitter portion having its axis perpendicular to the axis of the second waveguide has its launch or transmitter portion mounted in a controllably rotatable dielectric rod, such that rotation of the rod causes rotation of the signal receiver portion for alignment with a selected one of the polarized signals.

Abstract: A mobile antenna unit for use in the FM broadcast band which is adapted to be mounted on the windshield of the vehicle and which provides a gain and directivity pattern similar to those of an external whip antenna. The antenna element takes the form of a conductor mounted near one of the pillars supporting the windshield. The pillar appears electrically as an inductor and the conductor as a capacitor. By properly dimensioning and spacing the conductor with respect to the pillar, resonance is achieved in the FM broadcast band.

Abstract: An electrically-small, cavity-backed slot antenna includes an electrically conductive sheet having an elongated slot contained within the perimeter of the sheet backed by a cavity formed in an electrically conductive housing connected to the sheet. A dielectric layer composed of material having a dielectric constant of ten or greater is coupled to the conductive sheet and overlies the slot so as to effect a reduction of the resonant frequency of the antenna which permits the antenna to be characterized as electrically small. Transmission conductors are electrically coupled to the conductive sheet across the slot and adapted to carry r.f. energy either to or from the sheet depending upon whether the antenna is being used in a transmit or receive mode. For fine tuning the resonant frequency of the antenna, a pair of capacitive elements are mounted across the slot and electrically coupled to the conductive sheet on opposite sides of the slot and at symmetrical loctaions therealong.

Abstract: A directional antenna for an electromagnetic sensing system comprises a generally cylindrical tube of electrically-conductive material a portion of the tube being cut away to define a transversally-facing window. The non-cut away portion of the tube provides a backing shield for a pair of antenna elements mounted on a generally `V`-shaped support. A cover of dielectric material is arranged over the antenna elements.

Abstract: A flush-mounted radiating antenna is disclosed which can be electronically switched to produce a rotating directional field with no moving parts in the antenna element itself or with the appropriate electronics in the entire mechanism. This is accomplished by utilizing pie-shaped sections on the flush surface which are capacitively coupled to a central feed element and shorting some of the pie-shaped capacitively coupled elements to a ground plane whereby the normally omnidirectional pattern is perturbed to a directional pattern.

Abstract: An electrically small, dual polarized, hemispherical coverage, multi-element adaptive array antenna exhibiting low VSWR and operational over an octave of bandwidth is flush-mounted with the airframe structure of high performance aircraft. The antenna is configured as a cavity type structure in the shape of a regular polygon and has a plurality of radiation elements mounted on an insulative support board, each of the elements being is connected to a respective output port for use in a multi-channel adaptive array system. The array provides broadband capability of nulling interfering sources having arbitrary polarization and spatial direction.

Abstract: A broadband cup antenna comprises dipole means having at least one pair of short spiral type monopoles diametrically disposed in a common plane in proximity to the open end of the cup. Parasitic elements are in juxtaposition with the monopoles and are electrically connected by a conductive ring mounted about coaxial lines. A circumferential slot formed in the outer conductor of the coaxial line adjacent to the monopoles serves for excitation of the monopole elements to effectuate signal transmission.

Abstract: A cylindrical cavity-backed multipole antenna system for high frequency applications is disclosed. The antenna system comprises a plurality N of planar radiation elements disposed on a dielectric disc mounted on the top surface of a conductive cylindrical cavity and equally spaced about its axis. A network circuit is adapted to introduce, for the system sum signal, progressive phase shifts of 360.degree./N to signals associated with adjacent elements and, for the difference signal, progressive phase shifts of 720.degree./N. The antenna system may be used to both transmit and receive electromagnetic radiation. The antenna sum and difference patterns are substantially symmetric in space about the antenna boresight.

Abstract: A broadband multi-element antenna is presented. The antenna comprises a monopole centrally disposed within a cavity of the body, and a plurality of antenna elements disposed at ninety degree increments about the periphery of the cavity. A plurality of isolation traps are connected between selected pairs of the antenna elements. The isolation traps are half-wavelength transmission lines which permit excitation of the respective plurality of elements by input signals which are of equal amplitude and 180.degree. out-of-phase but are short circuits between the respective pairs for in phase signals parasitically induced from the monopole. Additionally, switching traps are connected to respective ones of the antenna elements. The switching traps comprise quarter-wave transmission lines which are switchable to ground and selectively provide a short circuit of signals at the respective ones of the elements for changing the radiation pattern of the antenna.

Abstract: A flush mounting, cavity-backed, dual orthogonal slot antenna in which improved radiation pattern characteristics are obtained by making the spiral slot pattern elliptical in the aperture plane. A cavity (11) and a flanged aperture plate (11a) are shown in which one slot pair (12 and 13) is orthogonal with respect to another slot pair (14 and 15) within the aperture plate (11a). Coaxial split-tube baluns (12a and 14a) are used to drive the junctions between corresponding slot pairs. Optional cavity dielectric (18) is provided and a drive coupling arrangement includes a four port comparator hybrid (30) having .ltoreq. and .DELTA. ports (17 and 16) respectively, for alternate excitation to produce a single lobe or a double lobe pattern with null. Switching apparatus is provided to connect a common terminal (26) to either of the ports (17 or 16).

Abstract: A microwave radiator comprises a generally cup-shaped, at least partly metallic cavity with a cylindrical wall and an open end which is bounded by an edge or rim with two diametrically opposite axial projections, in the form of acute-angled cusps or rectangular teeth, which are bisected by an axial plane perpendicular to a dipole disposed inside the cavity. The open cavity end may be covered by a dielectric radome of frustoconical or stepped cylindrical configuration.

Abstract: A broadband antenna element capable of operating over greater than an octave band of frequencies is disclosed. The element comprises an open-ended rectangular waveguide section having a loop radiator, formed by shorting an insulated probe to one of the broad walls of the waveguide section, disposed therein. Notches are provided in the narrow walls and flanges are provided on the broad walls of the waveguide section for matching purposes. The insulated probe extends through a hole formed in the rear wall of the waveguide section to connect with a stripline feed network.

Abstract: Apparatus for sensing the presence of one or more of a multiplicity of radio waves of distinct frequencies, using a single horn and one or more radiation-receiving apertures with associated circuitry.

Abstract: Disclosed is a coaxial antenna array for communicating circularly polarized electromagnetic radiation. A pair of open ended antenna cavities is coaxially constructed and operates by excitation of linear radiation elements arranged within each of the cavities. A pair of crossed-dipole radiation devices are centered within the inner cavity and operated by means of a phase-shifting network circuit to transmit as well as receive circularly polarized radiation. Four monopole radiation devices are symmetrically arranged to operate in the outer cavity in phase quadrature by means of the phase-shifting network circuit to also both transmit and receive circularly polarized electromagnetic radiation. Combined operation of the two antenna cavities with a 180.degree. phase differential between the fields related to the two antenna cavities provides a broad beam, relatively wide frequency bandwidth communication capability.

Abstract: An array antenna is disclosed wherein each one of the antenna elements includes at least two concentric slots formed in a conductive sheet. The conductive sheet is disposed on a dielectric support and a ground plane is found on the opposite surface of such support. The inner one of the slots enables the outer slot to radiate radio frequency energy having a wavelength greater than the circumference of such outer slot. When such antenna includes an additional concentric slot the antenna is adapted to operate over a pair of frequencies separated by greater than twenty percent while enabling the array antenna to have satisfactory grating lobe characteristics.

Abstract: A dual frequency band directional antenna or system in the form of a cavity reflector antenna mechanically combined and radiation-coupled with a loop of approximately the same shape and periphery as the rim edge of the cavity reflector, which loop is arranged outside and in front of, and in close proximity and parallel to the cavity rim edge, and, when properly energized, acts for the lower frequency band as a loop radiator with preselected field polarization, whereby the entire cavity structure serves two purposes by acting simultaneously as reflector for the higher frequency band cavity reflector antenna and for the lower frequency band, electrically separate loop radiator, with the radiation patterns of both sources being unidirectional over both frequency bands and with their radiation maxima directed into the center axis normal to the bottom plate of the cavity reflector structure.

Abstract: A radio frequency antenna having a flared, discontinuous slot formed on one surface of a dielectric support structure and a feed formed on the opposite surface of such structure. The feed is disposed across a narrow portion of the slot. A housing having a cavity formed therein is provided. The dielectric support is disposed on the housing over the cavity. The cavity has a conductive wall, or deflective plate, disposed beneath a wide portion of the slot. The effects of the feed and the slot-deflection plate combine to provide a flush-mountable antenna having a cardioid-shaped radiation pattern.

Abstract: A resonant circularly or elliptically polarized microstrip radiator wherein the size of the radiator is reduced in the resonant or non-resonant dimensions, or both, without reducing the effective resonant dimension or substantially lowering the efficiency of the radiator. Reduction of the resonant dimension is provided by folding the resonant cavity, while reduction of the non-resonant dimension is facilitated by utilization of a low density, low loss dielectric, such that the loss resistance of the element is appreciable with respect to the radiation resistance of the element. The preferred embodiment comprises interdigitated antenna structures.

Abstract: A microstrip antenna wherein a cavity or channel is formed in the ground plane conductor to reduce radiation losses and cross-coupling between elements. A shielded embodiment is also disclosed.

Abstract: A miniature, flush mounted, microwave dual band antenna which radiates omirectional microwave signals from a single flush mounted cylindrical array at frequency bands separated by 1.5 octaves. The antenna has a Y-shaped cavity with the leg of the Y being taken up by a probe and surrounding dielectric block. The cavity resonates the lower frequency band energy primarily in the open non-dielectric spaces and resonates the higher frequency band energy primarily in the dielectric space.

Abstract: A rectangular antenna has a T-bar of planar cross section for providing a axial to cavity transition. A narrow slot having a length equal to one half the wavelength of the upper end point of the frequency range utilized is centered within the T-bar. Tuning stubs are located in predetermined positions directly under the T-bar for reducing the effect of the TE.sub.30 mode.

Abstract: A broadband omnidirectional slot antenna suitable for transmission of television signals employing a wide slot and a wide, long strap between a feed point and the slot edge.

Abstract: The radiation absorber system of a unidirectional spiral antenna is provided with a laterally transverse variable radiation absorption density characteristic to control the absolute gain with frequency pattern, i.e. absolute gain versus frequency characteristic, of the antenna.

Abstract: A cavity antenna having an aperture which may be mounted flush to the gro plane. A chamber positioned above a rectangular resonant cavity allows the antenna to achieve normal bandwidth and normal gain with a very thin cavity depth.

Abstract: A thin omnidirectional antenna suitable for mounting and operation flush to ground plane. A flat metal probe is sandwiched between a pair of dielectric vanes which are enclosed in turn by a pair of metallic T-guides within a radiating cavity. The design achieves resonance for efficient radiation within an electrically small cavity.

Abstract: An apertured metallic ground plate antenna element having a high input impedance is driven from a lower impedance input transmission line by means of an exciter that provides broadband impedance transformation. The input transmission line is divided into two higher impedance feed lines that feed two parallel plate transmission lines. The parallel plate transmission lines are positioned in close proximity to the element aperture and are oriented to provide antenna excitation in series.