Abstract: A method of two-source passive ranging comprising the steps of determining the coordinates of a first position and a second position wherein a first soldier or ground vehicle is located at the first position and a second soldier or ground vehicle is located at the second position; determining individual angles between said first and second positions and a radio frequency source; and using individual single-angle accuracy values to estimate the range from the first and second positions to the radio frequency source.

Abstract: An orientation-independent antenna that presents a circular polarization characteristic to incoming waves such that these waves are detected regardless or polarization and angle of arrival is provided with shorts across elements thereof that provide for crossed vertical loops and a horizontal loop to lower the VSWR at the lower frequencies of the antenna. The antenna includes crossed vertical loops and a horizontal loop, with the loops being phased to provide the circular polarization characteristic. In one embodiment, the antenna includes a number of elements on the faces of a cube, or the elements are positioned on the surface of a sphere. In another embodiment, the antenna is given both a right hand circular polarization characteristic and a left hand circular polarization characteristic in two different channels to provide for double the data throughput.

Abstract: A miniature volumetric spherical geometry with multiple symmetric feeds is spaced from the surface of the vehicle or platform, with the antenna exhibiting both circular polarization that is orientation-independent or angle of arrival independent, while at the same time covering a broad band of frequencies from 243-318 MHz in one embodiment.

Abstract: A miniature conformal antenna is provided with a polarization-independent output by using quadrature elements at the mouth of a cavity and by processing the RHCP and LHCP outputs of the elements to arrive at a polarization-dependent solution; and then correcting the angle of arrival result by electronically rotating the antenna, measuring the amplitude difference between element pairs at various angles, generating an amplitude difference curve and deriving an angular correction factor therefrom.

Abstract: An orientation-independent antenna presents a circular polarization characteristic to incoming waves such that these waves are detected regardless or polarization and angle of arrival. The antenna includes crossed vertical loops and a horizontal loop, with the loops being phased to provide the circular polarization characteristic. In one embodiment, the antenna includes a number of elements on the faces of a cube, or the elements are positioned on the surface of a sphere. In another embodiment, the antenna is given both a right hand circular polarization characteristic and a left hand circular polarization characteristic in two different channels to provide for double the data throughput.

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 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. The antenna incorporates chokes that may be implemented using meanderline techniques.

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 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.

Abstract: A switched meander line structure is substituted for a lumped element antenna tuner for an order of magnitude increase in gain due to the use of the switched meander line architecture. The use of the meander line 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 tuner.

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 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 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: 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 hemispherical meander line loaded antenna is provided which can fit within a hemispherical radome 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 equalize the reactance of the antenna, thereby to enable proper impedance matching.

Abstract: The combination of a Vivaldi slot and a meander line loaded antenna is provided which exhibits an ultra wideband characteristic with the Vivaldi notch expanding the high end and with the meander line loaded antenna portion reducing the low frequency cut-off. When these antennas are arrayed, this array exhibits a single lobe and an ultra wide 100:1 bandwidth. The Vivaldi notch portion of the antenna accommodates the higher frequencies, whereas the meander line loaded antenna portion of the antenna accommodates the lower frequencies, there being a smooth transition region between the Vivaldi and meander line portions of the antenna and no discontinuity. In one embodiment, the antenna is made to work between 50 MHz and 1500 MHz with a VSWR less than 3:1. The Vivaldi notch meander line combination assures that for an array one does not have a separation of the elements more than a 0.5 wavelength at the highest frequency, thus to eliminate the possibility of creating grating lobes.

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: 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: 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.