Abstract: A method is provided for estimating an antenna gain for an antenna under test (AUT). The AUT is positioned above a lossy surface and a probe antenna is positioned at a test distance from the AUT. A known signal is emitted from the AUT and received at the probe antenna. Utilizing the calculated normalized potential, the AUT gain can be estimated at any distance from the AUT. An apparatus is also provided.

Abstract: An antenna capable of being joined to an antenna feed perpendicular to a ground plane includes a conductive radiator and a circular wafer surrounding the radiator. The radiator is tubular and has a longitudinal slot along the entire length thereof, parallel to the radiator's axis. The antenna feed can be connected across the slot. The wafer, made either or a conventional high dielectric isotropic material or of a uniaxial dielectric material, is spaced apart from the radiator and has a thickness approximately equal to the width of the slot, a diameter wherein a ratio of a diameter of the radiator to the diameter of the wafer is approximately 35%, and is located at a height above the ground plane equal to approximately 35% of the length of the radiator. The material of the wafer has a dielectric tensor with high polarizability in the axial direction and can be applied to preexisting antennas. This antenna gives enhanced bandwidth over ordinary slotted antennas.

Abstract: A dual mode antenna can be joined to an antenna feed. The antenna includes a slotted cylinder radiator that can be connected to the first conductor of the antenna feed and an electrically conductive ground plane that can be connected to the second conductor. The radiator axially extends perpendicularly from the ground plane and is electrically insulated therefrom. The first conductor can be joined to the radiator near one side of the slot. A reactive load is joined between the ground plane and the radiator near an opposite side of the slot. The reactive load impedes lower frequencies from the ground plane to the radiator. This allows the radiator to function as a monopole at lower frequencies and a slotted cylinder at higher frequencies.

Abstract: An antenna capable of being joined to an antenna feed perpendicular to a ground plane includes a monopole extending perpendicularly from the ground plane. The antenna feed is joined to the monopole. An innermost shell is provided about the monopole. The innermost shell is made from a dielectric material having a dielectric tensor with high permittivity in the direction of the monopole axis. An intermediate shell provided outside the innermost shell. The intermediate shell also has dielectric tensor having high impedance in the direction parallel to the monopole axis. An outermost shell is provided having a perimeter approximately equal to the length of the monopole. The outermost shell also has a dielectric tensor with high impedance in the direction of the monopole axis.

Abstract: An antenna for connection to a feed includes a substrate with a conductive ground plane. An emitter is positioned on the top face of the substrate, and the feed is connected to the emitter and ground plane. A spacer is positioned on the substrate above the emitter and one layer of high dielectric constant rods is positioned above the spacer. The rods are positioned in a single plane, coplanar with the emitter, and parallel to the dominant current distribution when the emitter is active. Further layers of spacers and rods can be positioned at a predetermined angle to the rods beneath. A kit is further provided for application of spacers and rods to preexisting antennas.

Abstract: An antenna capable of being joined to an antenna feed perpendicular to a ground plane includes a conductive radiator and a cylindrical shell. The conductive radiator is tubular and has a longitudinal slot along the entire length thereof. The slot is parallel to the radiator's axis. The antenna feed can be connected across the slot. A cylindrical shell of a uniaxial dielectric material is provided outside and spaced apart from the conductive radiator and extends beyond ends of the conductive radiator. The cylindrical shell electrically contacts the ground plane. The shell is made from a material having a dielectric tensor with high impedance in the axial direction. This antenna gives enhanced bandwidth over ordinary slotted antennas. The shell can be applied to preexisting antennas.

Abstract: An antenna for connection to a feed includes a substrate with a conductive ground plane. An emitter is positioned on the top face of the substrate, and the feed is connected to the emitter and ground plane. A spacer is positioned on the substrate above the emitter and one layer of high dielectric constant rods is positioned above the spacer. The rods are positioned in a single plane, coplanar with the emitter, and parallel to the dominant current distribution when the emitter is active. Further layers of spacers and rods can be positioned at a predetermined angle to the rods beneath. A kit is further provided for application of spacers and rods to preexisting antennas.

Abstract: A cylindrical antenna includes: a hollow cylinder having a height, an inner radius b, an axis, a cylindrical surface, and two ends; a ground plane on one end of the cylinder; an antenna wire extending from a center of the cylinder at one end on a ground plane along the axis and ending below the height of the cylinder; and a layer of near zero index (NZI) metamaterial surrounding and adjacent to the cylindrical surface.

Abstract: An antenna includes a polymer coating having a VLF/LF element and an HF/VHF element embedded therein. A blocking choke is interposed between the VLF/LF element and the antenna feed t block HF/VHF signals. Small chokes are regularly positioned on the VLF/LF element to eliminate resonances caused by mutual capacitance between the elements. Reactive loads are positioned in said HF/VHF element at regular intervals for optimizing performance of the antenna in the HF/VHF radio bands. In further embodiments the antenna is provided as a floating antenna with the elements helically arranged therein.

Abstract: An antenna can be joined to an antenna feed and positioned perpendicular to a ground plane. The antenna includes a conductive radiator having a cylindrical portion. A slot is formed in the entire length of the cylindrical portion. Two parallel fins extend from the cylindrical portion at the slot. The fins can extend inwardly or outwardly. The antenna feed is connected to the conductive radiator on either side of the slot. An anisotropic magnetic material having a uniaxial permeability tensor is positioned in the slot between the two fins. This material is oriented such that it has a much greater permeability in the radial direction than in the other directions. The interior of the cylindrical portion can be filled with a dielectric material.

Abstract: An antenna capable of being joined to an antenna feed and being positioned perpendicular to a ground plane includes a conductive cylinder having a longitudinal slot. The antenna feed is connected across the slot. A plurality of dielectric rods are provided parallel to the slot with rod being positioned much less than one wavelength of the maximum operating frequency away from adjacent rods. The rods each have a length of at least 25 times its mean diameter is made from a material having a dielectric constant greater than 30. The combination of the conductive cylinder and dielectric rods provides increased bandwidth. A kit for modifying existing antennas is further provided.

Abstract: An antenna includes a polymer coating having a VLF/LF element and an HF/VHF element embedded therein. A blocking choke is interposed between the VLF/LF element and the antenna feed t block HF/VHF signals. Small chokes are regularly positioned on the VLF/LF element to eliminate resonances caused by mutual capacitance between the elements. Reactive loads are positioned in said HF/VHF element at regular intervals for optimizing performance of the antenna in the HF/VHF radio bands. In further embodiments the antenna is provided as a floating antenna with the elements helically arranged therein.

Abstract: An antenna includes a first antenna section that can be joined to an antenna feed. The first section has conductive elements in series with reactive loads. The reactive loads are positioned with a regular spacing. The reactive loads and spacing are optimized for operation of the first section at the highest frequency. Additional antenna sections having successively lower frequencies are joined in series to the first antenna section. Each additional section has conductive elements joined in series with reactive loads at a particular spacing. The additional sections spacing and reactive loads are provided to work in conjunction with the higher frequency antenna sections to optimize the antenna for an additional frequency. A method for making such an antenna is further provided.

Abstract: An antenna includes a polymer coating having a VLF/LF element and an HF/VHF element embedded therein. A blocking choke is interposed between the VLF/LF element and the antenna feed to block HF/VHF signals. Small chokes are regularly positioned on the VLF/LF element to eliminate resonances caused by mutual capacitance between the elements. Reactive loads are positioned in said HF/VHF element at regular intervals for optimizing performance of the antenna in the HF/VHF radio bands. In further embodiments the antenna is provided as a floating antenna with the elements helically arranged therein.

Abstract: An antenna includes a tubular, conductive radiator having a longitudinal slot formed therein from a first end of the conductive radiator to a second end of the conductive radiator. An antenna feed can be joined to the conductive radiator adjacent to and across the slot. An anisotropic plate is positioned a uniform distance from the conductive radiator, centered above the slot. The plate extends beyond the length of the radiator and is electrically insulated therefrom. An anisotropic tube surrounds the plate and radiator. The anisotropic tube is electrically insulated from the plate and radiator. In use, this antenna gives enhanced bandwidth over ordinary slotted antennas. This can also be applied to preexisting slotted antennas for enhanced bandwidth.

Abstract: A method for improving bandwidth and gain of a microstrip patch antenna and a microstrip patch antenna are provided. The method includes forming a highly anisotropic superstrate, and positioning the highly anisotropic superstrate at a predetermined distance away from the ground plane side of the microstrip patch antenna, increasing the bandwidth of the microstrip patch antenna. The antenna provides a microstrip patch antenna having a highly anisotropic superstrate. The highly anisotropic superstrate can include a spacing layer, a dielectric material positioned on the spacing layer and a plurality of conductive strips disposed on the dielectric layer.

Abstract: The invention as disclosed is a buoyant cable antenna configured for both VLF/LF and HF signals. A 100 foot antenna element has a low-pass filter assembly positioned at the midpoint of the antenna element to block HF signals. The outboard tip of the antenna element is shorted. In this way, the antenna element appears as a 50 foot open circuit antenna element to HF signals and as a 100 foot shorted antenna element to VLF/LF signals.

Abstract: An antenna element with a single-conductor antenna is provided within a removable core. The removable core is mounted within a hollow liner by sliding the core into the hollow liner. A pull cable may be attached to an end of the removable core to pull the core through the outboard end of the hollow liner. Due to reduced strain on the core as compared to the liner, the single-conductor antenna may be formed in segments interconnected with capacitors for adjusting the antenna gain to a maximum in the vicinity of a desired operating frequency or frequencies.

Abstract: A hybrid cable antenna includes a first cable antenna that is buoyant and unloaded for operation in a lower portion of the high frequency band. At least one second cable antenna is serially and electrically coupled to the first cable antenna. Each second cable antenna is buoyant and loaded for operation in a portion of the high frequency band that is above the lower portion of the high frequency band.

Abstract: A remote power delivery system includes an electrically-conductive plate disposed adjacent to a sensor system of an underwater vehicle's hull. At least one toroidal coil is disposed between the plate and the face of the sensor system exposed to water. An AC voltage is applied to the plate so that a time-harmonic voltage is induced in each toroidal coil.