Abstract: A hybrid antenna in which the flared end of a parallel plate of a transmion line is coupled to a frequency independent antenna so as to take the place of the higher frequency radiating portion of the antenna.

Abstract: A detectable device attachable to a movable item for detecting movement. Radio waves having a predetermined frequency are received by the detectable device, and radio waves having a harmonic frequency of the received waves are reradiated from the detectable device. The detectable device comprises a dipole antenna for receiving radio waves with said predetermined frequency, a diode connected in parallel to feed points of the dipole antenna for generating an electric current having a harmonic frequency of said received radio waves. A loop antenna is provided whose feed points are connected in parallel to feed points of the diode for converting the electric current having the harmonic frequency to radio waves for transmitting the radio waves at the harmonic frequency.

Abstract: An antenna system is described including a reflector antenna, responsive to radio frequency signals at a first frequency, having a first reflector surface, a second reflector surface and a Cassegrain feed. The antenna system further includes an array antenna having a plurality of antenna elements responsive to radio frequency signals having a second different frequency, wherein a center element is in a common location with the feed of the reflector antenna. With such an arrangement, an improved dual band antenna system is provided. By providing the center element of the array antenna in a common location with the feed of the reflector antenna, a dual band radio frequency antenna system is provided which is more compact with improved radiation characteristics than known similar configured antennas.

Abstract: An antenna system capable of receiving electromagnetic radiation having either right or left helical polarization, and either vertical or horizontal linear polarization includes an energy concentrator which concentrates energy at a focal point. A helical antenna is arranged in the proximity of the focal point. A first switch switches the helical antenna to a backfire mode of operation and a second switch switches the helical antenna to an end fire mode of operation. A control mechanism controls the switches to select the nature of the polarization.

Abstract: An antenna device is withdrawable from and receivable in a body of a portable radio device. A rodlike antenna is covered with a rodlike antenna cover, and a helix antenna to which an initial elastic strain is imparted is covered with a cap. A control portion of an electrically-conductive member is movably received in a groove formed in a portion of connection between the rodlike antenna cover and the cap. The rodlike antenna cover is supported on the body of the radio device. In an extended condition of the rodlike antenna, a connection portion of the electrically-conductive member is urged against the rodlike antenna by a restoring load of the helix antenna to electrically connect the spiral antenna to the rodlike antenna. In a retracted condition of the rodlike antenna, the electrically-conductive member is caused to abut against an antenna holder to be spaced apart from the rodlike antenna, thereby interrupting an electrical connection between the helix antenna and the rodlike antenna.

Abstract: A direction finding system utilizing a single monopole/crossed slot antenna in combination with associated electronic circuitry. Each of the four ports of the antenna are connected to amplitude varying elements whose outputs are combined by a power combiner. A microcontroller stores the signal. The microcontroller also generates the signals which control the amplitude variation supplied by each of the amplitude varying elements. Two configurations of the amplitude varying elements are provided by predetermined settings within the microcontroller. The two settings are selected to configure the antenna on two distinct reception patterns, each with a predetermined angular offset from a reference direction. In operation the antenna will be configured for a first reception pattern. The signals received will be detected, quantified, and stored by the microcontroller which subsequently reconfigures the antenna for a second reception pattern.

Abstract: A conductive layer is formed on one surface of an insulating substrate. Notches are formed in the conductive layer to be axially symmetric at equal angular intervals of 120.degree.. A feeding line of a notch antenna is formed on the other surface of the substrate. The feeding line has a C-shape and wide portions for adjusting the phases of excitation of the notches, and receives power at its one point. A ground plate is arranged to be parallel to the substrate. A feeding rod is connected to the conductive layer. The conductive layer and the ground plate are short-circuited by impedance matching pins. The matching pins are integrally formed with the ground plate. The notches and the feeding line constitute an notch antenna, and the feeding rod, the ground plate, the conductive layer, and the matching pins constitute a capacity loaded monopole antenna. To resonate these antennae at a plurality of resonant points, slits are formed in the conductive layer to be axially symmetric at equal angular intervals of 120.

Abstract: New type of planar antenna of microwaves appropriate for operating in linear and circular polarization, free of welds and floating potentials, and therefore free of electrostatic discharges and problems related to passive intermodulation products, whose application is of particular interest in aircraft and space technologies. The antenna consists in the interconnection of a microstrip radiator with a spiral antenna of wires. For certain applications wherein the radiators are arranged in a same plane, the radiating effect of the patch may reduce the size of the spiral.

Abstract: A double-folded monopole is used on a linear antenna to produce a traveling-wave distribution of current. The double fold is positioned one-quarter wavelength from the end of the antenna. The resultant antenna has three radiating elements that are orthogonal with respect to each other. The orthogonal folded dipoles each consist of five segments designed so that the currents have comparable magnitudes and are in phase to provide near hemispherical coverage.

Abstract: The present invention pertains to an end-fed rod antenna which is tuned, e.g., to the VHF range and has additional transmitting and/or receiving antennas for the mm-wave range.

Abstract: A resonant antenna suitable for transmission and for reception over a broad range of frequencies combines electric and magnetic multipoles generated by linear and loop elements respectively. The minimum requirement is one electric and one magnetic dipole and one electric and magnetic quadrupole. The electric elements are driven in time quadrature with the magnetic elements. The elements of the minimum requirement lie in the same plane and along the same axis. The minimum number of elements for a free standing antenna is three loops and three dipoles. Maximum transmission and reception occur only in the same direction along the axis. The size of the antenna is reduced by introducing a ground conductor or plane along the antenna axis and eliminating the half elements on one side thereof and is further reduced by introducing a second ground plane normal to the first at the midpoint of its length and eliminating the quarter elements on one side.

Abstract: A two-frequency planar antenna incorporates a resonant antenna and a slot antenna which are arranged in a superposed manner on the same dielectric substrate so as to be operable independently without interfering with each other. The two-frequency planar antenna includes a front conductor plate arranged on one surface of a dielectric substrate to serve as a radiation conductor plate of a resonant antenna and a slotted conductor of a slot antenna, a back conductor plate arranged on the other surface of the dielectric substrate to serve as a grounding conductor of the resonant antenna and a reflector of the slot antenna, and a slot antenna feed line embedded in the dielectric substrate. The slot antenna feed line is arranged along an axis where an electric field in an excitation mode of the resonant antenna is reduced to zero and at least one slot is formed in the front conductor plate along the feed line.

Abstract: A wideband antenna with reduced diameter and volume compared to prior art tennas and having non-critical dimensions resulting in ease of manufacture and tolerance to damage in portable applications and during installation. In one embodiment the antenna is comprised of a vertical element, a number of equally spaced, equal length horizontal elements in the form of a disc and a number of equally spaced, equal length round plane elements in the form of a cone. The vertical and horizontal elements are connected to the inner conductor of a coaxial transmission line and the conical elements are connected to the outer conductor transmission line. In a second embodiment of the present invention, the vertical element is deleted and a parallel inductor is connected between the transmission line outer and inner conductors.

Abstract: A reduced height monopole/crossed slot antenna having generally parallel spaced ground planes, the upper one of which has a capacitively loaded slot therein formed by crossed slot portions. A stripline is located between the ground planes offset toward the upper ground plane, and is formed by crossed stripline portions. A monopole extends from the intersection of the crossed stripline portions through the intersection of the crossed slot portions orthogonally to the upper ground plane, and is top hat loaded at the outer end thereof. The stripline is fed at selective ends thereof.

Abstract: A reduced height monopole/slot antenna having generally parallel spaced ground planes, the upper one of which has a slot therein, a stripline located between the ground planes, and a monopole extending from the stripline through said slot generally orthogonally through the upper ground plane and being top hat loaded at the outer end thereof. The stripline is offset toward the slotted ground plane, and the slot is capacitively loaded with capacitance connected across the narrow dimension of the slot.

Abstract: A planar antenna is described which employs a pair of closely spaced parallel ground planes and a radiating element which is a composite aperture (hybrid slot) formed into the upper ground plane. One portion of the radiating element is a long narrow slot which may have the shape of a rectangle of high aspect ratio. The other portion is an annular slot which may be circular in shape. Electromagnetic energy is conveyed to and from the slots in the upper ground plane by means of a feed conductor parallel to and sandwiched between the two ground planes. The maximum of the resulting field pattern is in the plane of the antenna and the pattern may be either directional or omnidirectional in that plane. When used as a receiving antenna, this antenna responds to both the electric and magnetic fields.

Abstract: A microstrip antenna having a plurality of different radiating elements sed apart in an end-to-end arrangement, above a ground plane and separated therefrom by a dielectric substrate; only one element is fed at its feedpoint, and energy emanating from the fed element is primarily coupled at one end to parasitic element(s) by the electric field generated in the fed element. The radiating pattern is determined by the phase relationship and amplitude distribution between the excited fed element and the parasitic element(s).

Abstract: The disclosed common aperture seeker antenna includes a parabolic array of crossed dipoles. This array is substantially reflective for radiated electrical signals in one band, and substantially transmissive for radiated electrical signals outside of that band. A monopulse (four-element) waveguide feed is rigidly positioned on the concave side of the parabolic array at the focal point thereof. The parabolic reflector antenna operates in the one band to provide a high gain active system for accurate tracking of targets. A planar spiral antenna is rigidly positioned on the convex side of the parabolic array in axial alignment with the parabolic reflector antenna. This wideband antenna operates over a multioctave frequency band below that of the one band to provide a low gain system for passive tracking of targets. The two antenna systems coexist in such a manner that each utilizes the available aperture to its fullest extent.

Abstract: Disclosed is an antenna for use in transmitting and/or receiving both optical, including infrared, and high-frequency electro-magnetic radiation. The antenna is comprised of a hollow conductor in the interior of which is arranged a light conductor as a dielectric. Arranged in the wall of the hollow conductor is at least one slot which acts as an input and/or output coupling opening for the hollow conductor and as an inlet and/or outlet window for optical radiation. Also disclosed is an antenna assembly unit consisting of a plurality of the individual antennas arranged to give omni-directional capabilities for receiving and transmitting of optical and high-frequency electro-magnetic radiation.

Abstract: This relates to dual band waveguide radiating element for an antenna. A pair of adjacent rear wall excited waveguide elements have a slot in the common wall between them. This slot contains an excitation element so that the structure operates as a ridge waveguide. The rear wall excitation is at the higher of the two frequencies, e.g. S band, while the ridge waveguide operates at the lower frequency, e.g. L band.

Abstract: A high accuracy broadband antenna system is disclosed. This system is a dual mode system which includes a parabolic reflector dish having a dielectric substrate and a conductive material coating on the substrate; an antenna feed positioned at the focus of the paraboloid and directed at the reflector dish for providing a narrow beam monopulse radiation pattern; and a circuit for coupling energy to and/or from the antenna feed. The conductive material coating on the reflector dish substrate defines a plurality of conductive spiral arms for providing a wide beam monopulse radiation pattern; and the antenna system further includes structure defining a cavity for backing the conductive spiral arms and a circuit for coupling energy to and/or from the conductive spiral arms, whereby the parabolic reflector dish is operable as a primary antenna providing a wide beam radiation pattern.

Abstract: A plurality of antennas attached to the glass of the rear window of a vehicle produces patterns that may be combined to give directional pick up patterns. The first basic antenna is two spaced vertical whip antennas connected by parallel horizontal delay lines. Each whip output has a cardioid pick up pattern in the direction of the other antenna, in this case to the right and left. The second antenna is connected vertically across the window opening. Its output has a figure eight pick up pattern, typical of a slot antenna, with the lobes to the front and rear of the vehicle. The phase relationship of these three pick up patterns are such that if properly combined, then either of two sets of pick up patterns can be obtained. The first pattern is the basic right and left cardioid, and the second pattern is the front and rear cardioids. When used in combination with a communications receiver and processor, the direction of the transmitter can be determined, regardless of which quadrant it lies.

Abstract: A dual mode high-frequency printed circuit radar antenna for aircraft use having good aerodynamics is provided in the form of a printed circuit antenna molded into a smooth, blade-like protective shield. The antenna, printed on an epoxy glass substrate carried on a mounting plate including, integrated in series, a stub monopole element and a larger area capacitive loading member for I-band reception, an inductive member whose impedance is very high at I band and a monopole element which adds sufficient length that the entire conductor track acts as a quarter wave length monopole at C and D bands. At I band the stub monopole element and capacitive loading is isolated from the added monopole element by the high impedance inductive member, making for good I-band performance.

Abstract: A VHF/UHF communications blade type antenna additionally having microwave nding system (MLS) antenna elements mounted thereon and having the microwave feed components integral therewith to provide a composite structure adapted to function both as a communications and as a navigation antenna. The antenna is particularly adapted for use with aircraft which is to be retrofitted to include MLS capability.

Abstract: A double omni-directional antenna for use with a transponder is disclosed allowing simultaneous operation within two different frequency bands. A double coaxial line is provided having outer, central, and inner concentric conductors. The outer and central conductors form a coaxial feed for a lower frequency antenna and the central and inner connectors form a coaxial feed for a high frequency antenna. The higher frequency antenna is located directly above the lower frequency antenna and each is either a unipole for vertically polarized radiation or a slot radiator for horizontally polarized radiation.