Abstract: A multi-band whip antenna having a 30 MHz to 2 GHz bandwidth and an L-band dipole has its coverage extended up to 6 GHz by eliminating nulls and reducing VSWR problems that are cured through the utilization of a sleeve over the feedpoint of the L-band antenna. Chokes in the form of sleeves are provided at either end of the L-band dipole to shorten the L-band antenna for preventing reverse polarity currents at the L-band antenna feedpoint, with the antenna further including the use of double shielded meanderlines to provide improved performance between 410-512 MHz and in which a capacitance sleeve is added at the bottom of the L-band antenna to effectively elongate the antenna below the L-band to permit operation below 700 MHz.

Abstract: A multi-band whip antenna having a 30 MHz to 2 GHz bandwidth and an L-band dipole has its coverage extended up to 6 GHz by eliminating nulls and reducing VSWR problems that are cured through the utilization of a sleeve over the feedpoint of the L-band antenna. Chokes in the form of sleeves are provided at either end of the L-band dipole to shorten the L-band antenna for preventing reverse polarity currents at the L-band antenna feedpoint, with the antenna further including the use of double shielded meanderlines to provide improved performance between 410-512 MHz and in which a capacitance sleeve is added at the bottom of the L-band antenna to effectively elongate the antenna below the L-band to permit operation below 700 MHz.

Abstract: A coaxial antenna is implemented that combines a VHF and UHF antenna on a common radiating element. The antenna may further include a satellite antenna that, together with the VHF/UHF antenna fits into a whip antenna footprint.

Abstract: A coaxial antenna is implemented that combines a VHF and UHF antenna on a common radiating element. The antenna may further include a satellite antenna that, together with the VHF/UHF antenna fits into a whip antenna footprint.

Abstract: A coaxial antenna is implemented that combines a VHF and UHF antenna on a common radiating element. The antenna may further include a satellite antenna that, together with the VHF/UHF antenna fits into a whip antenna footprint.

Abstract: A coaxial antenna is implemented that combines a VHF and UHF antenna on a common radiating element. The antenna may further include a satellite antenna that, together with the VHF/UHF antenna fits into a whip antenna footprint.

Abstract: A method for early detection of faulty antenna arrays comprising the step of treating said detection as a special case of target recognition; wherein targets of interest are all previous examples of defective antenna arrays.

Abstract: A wideband meander line loaded antenna is configured to be flush mounted to a conductive surface serving as a ground plane by embedding the meander line components within a conductive cavity surrounded at its top edge by the ground plane. The antenna thus looks out of a cavity recessed in the surface. By permitting flush mounting the meander line antenna, not only can the antenna dimensions be minimized due to the use of the meander line loaded antenna configuration, but in aircraft applications no part of the antenna exists above the skin of the aircraft, thereby to minimize turbulent flow. Also disclosed is a method and apparatus in which a lossy dielectric is placed across the feed points of a loop type meander line loaded antenna to markedly decrease the VSWR to below 3: 1, thus to increase the bandwidth of a relatively wideband 3:1 meander line loaded antenna to 6:1.

Abstract: A nested cavity embedded loop mode antenna is provided with an ultra wide band response by nesting individual embedded cavity meander line loaded antenna modules, with the meander lines coupled to a ground plane plate either capacitively or directly so as to provide as much as a 27:1 ratio of high frequency to low frequency cutoff. The nested meander line structure is exceptionally compact and eliminates the problem of a null in the antenna radiation pattern perpendicular to the face of the antenna, thus to provide a loop type antenna pattern at all frequencies across which the antenna is to be operated. The use of the nested meander line configuration provides a flush mount for the antenna having a footprint associated with the larger of the meander line cavities and thus the lowest frequency of operation, the nesting precluding the necessity of providing separate side-by-side meander line loaded antennas which would increase the real estate required.

Abstract: A miniature broadband monopole antenna design configured with integrated band-selecting filtering is disclosed. The antenna is electrically folded, and includes top and bottom monopole sections, with a meanderline to provide an inductive load between the two sections. The overall antenna structure can be embedded in a relatively small, RF transparent, composite structure (e.g., such as the fin of a guided munition), and has minimal impact on aerodynamics (low drag). The top, bottom, and meanderline elements of the antenna operate together to collectively provide multi-band operation (e.g., 30 MHz to 3 GHz).

Abstract: A switched meander line structure is substituted for a lumped element coupler (10) for an order of magnitude increase in gain due to the use of the switched meander line architecture. The use of the meander line (20) with relatively wide and thick folded legs markedly decreases I2R losses over wire inductors whose wire diameters at one-tenth of an inch contribute significantly to I2R losses. Additionally, placing solid state switches to short out various sections of a multi-leg meander line at high impedance nodes reduces I2R losses across the switching elements in the coupler.

Abstract: An asymmetric slotted L-shaped antenna is provided with a wide bandwidth in an exceedingly small size with good gain across the entire bandwidth by shorting out one end of the slot and by providing a capacitor at the other end of the slot, with the result that with appropriate capacitance, spacings and dimensions, the impedance of the slotted transmission line cancels the reactance of the antenna such that the gain of the antenna can be made to match a similar sized meander line loaded antenna.

Abstract: A collapsible discone antenna is provided with an ultra wide band width by providing a collapsible conical skeleton cone, with the rods of the skeleton being provided with meander lines so as to effectively reduce the overall dimensions of the antenna by a factor of 2, with the antenna rods being electrically interconnected at their distal ends so as to eliminate performance degradation due to varying ground conductivities. A specialized feed configuration is used in one embodiment to feed multiple antennas stacked above a low band disc through the utilization of one or more coaxial lines which are wrapped around a ferrite toroid so that they may be passed up through the low-band disc without detuning the low band discone antenna. The use of the toroid inductor between the low-band cone and the low-band disc further reduces the low frequency cutoff of the antenna by markedly decreasing the VSWR at frequencies as low as 20 megahertz.

Abstract: A standard slow wave meander line having sections of alternating impedance relative to a conductor plate is provided with a top shield connected to the conductor plane for the purpose of lowering the resonant frequency of narrow band antennas and lowering the low frequency cutoff limit of wide band antennas due to a higher delay per unit length occasioned by the use of the top shield. The shielded meander line may be utilized as a coupling device to truncated antennas such as a whip antenna or grounded loop antenna for the purposes of loading the antenna so as to provide lower frequency performance. Since the propagation constant of the meander line structure depends upon the number of high impedance/low impedance transitions per unit length, the utilization of the top shield results in more phase shifts per unit length and thus more delay per unit length, with the symmetric double sided version having double the number of transitions per unit length.

Abstract: An inexpensive, small, low-power consumption, wide-band, high resolution spectrum analyzer is provided as a listening device for throw-away applications such as surveillance that involve deployment of large numbers of battery-powered spectrum analyzer modules to detect a signal source such as two-way radio traffic. Power requirements are minimized by the utilization of only one chirp generator to elongate battery life while providing a high resolution result. In order to minimize power drain the spectrum analyzer includes a single compound-chirp Fourier Transform generator. The compound chirp generator is used in one embodiment with a surface acoustic wave, SAW, dispersive delay line in conjunction with a surface electromagnetic wave, SEW dispensive delay line.

Abstract: A hemispherical meander line loaded antenna is provided which can fit within a hemispherical radome so as to minimize real estate on an aircraft such as an unmanned airborne vehicle. In one embodiment, a double monopole is recreated in a hemispherical form, thus to make what was originally a rectilinear package into a hemispherical package without materially affecting VSWR or ultra-wideband and antenna pattern characteristics. The wideband double monopole hemispherical meander line loaded antenna is provided with a single feed, with the delay associated with the meander lines of the antenna adjusted to equalize the reactance of the antenna, thereby to enable proper impedance matching.

Abstract: A gapless Vivaldi notch/meander line antenna is provided having a top plate with a Vivaldi notch, a cavity and a rearwardly-extending notch, with the top plate having integral side plates and a meander line bridging the rearwardly-extending notch at its distal end.

Abstract: A collapsible discone antenna is provided with an ultra wide band width by providing a collapsible conical skeleton cone, with the rods of the skeleton being provided with meander lines so as to effectively reduce the overall dimensions of the antenna by a factor of 2, with the antenna rods being electrically interconnected at their distal ends so as to eliminate performance degradation due to varying ground conductivities. A specialized feed configuration is used in one embodiment to feed multiple antennas stacked above a low band disc through the utilization of one or more coaxial lines which are wrapped around a ferrite toroid so that they may be passed up through the low-band disc without detuning the low band discone antenna. The use of the toroid inductor between the low-band cone and the low-band disc further reduces the low frequency cutoff of the antenna by markedly decreasing the VSWR at frequencies as low as 20 megahertz.

Abstract: An apparatus and method for detecting gases, gasified agents or other analytes. The apparatus includes a solid body having a first surface area and a second surface area. A first, preferably polymeric, coating is superimposed on the first surface area of the solid body. A second, preferably polymeric, coating is superimposed on the second surface area of this solid body. The first coating and the second coating are different materials which adsorb different agents at different rates. A wave propagating transducer is positioned adjacent the solid body to propagate a first wavefront adjacent the first surface area of the solid body. This wave propagating transducer also propagates a second wavefront adjacent the second surface area of the solid body. These first and second wavefronts interfere to produce an interference pattern which is unique to the particular agent which is adsorbed by the first and second coatings.

Abstract: The combination of a Vivaldi notch and a meander line loaded antenna for ultra wide bandwidth is provided with dual polarity by providing orthogonally oriented Vivaldi notched structures coupled to each other at the edges thereof. Mode selection is provided by selectively switching between linear and circular polarization modes through selective input coupling techniques. Each side of the dual polarity Vivaldi notch/MLA plates includes a bifurcated plate with one end of the bifurcated plate having exponentially curved Vivaldi notch surfaces ahead of a cavity opened at the rear end to the bifurcation notch. The side plates for the top plate structure are themselves Vivaldi notch structures, with their side plates being the ajoining top or bottom plate. In each case, internally carried meander lines connect the adjacent plates together.