Abstract: An antenna includes antenna structure configured to receive electromagnetic radiation and including an antenna geometry. The antenna geometry is configured to cause a variable phase shift in the electromagnetic radiation based on an angular position of a direction of propagation of the electromagnetic radiation relative to azimuth. An angle-of-arrival sensor includes the antenna configured to the receive electromagnetic radiation and to produce a phase-shift signal. A method for determining an angle of arrival of electromagnetic radiation uses the angle-of-arrival sensor.

Abstract: In examples, systems and methods for direction finding of electromagnetic signals are described. The device includes a first antenna configured to receive electromagnetic energy. The device also includes a second antenna configured to separately receive the same electromagnetic energy. The device further includes a radome located in a receiving pathway of the first antenna, where the radome is configured to cause a predetermined phase shift that varies based on an angular position of the receiving pathway. The device includes 1 or more radio receivers to receive the signals independently from the antennas. Additionally, the direction finding device includes a processor configured to determine an angle of arrival of the electromagnetic energy based on a comparison of a phase of the electromagnetic energy received by the first antenna to a phase of the electromagnetic energy received by the second antenna.

Abstract: A method for designing an antenna including defining an operating frequency of an antenna radiating element located within an antenna cavity structure; determining a non-loaded depth of the antenna cavity structure; determining a reduced depth of the antenna cavity structure; determining a reduction factor to reduce the non-loaded depth to the reduced depth; and selecting a dielectric material, at least partially forming a radome structure covering the antenna radiating element, to achieve the reduction factor.

Abstract: In examples, systems and methods for direction finding of electromagnetic signals are described. The device includes a first antenna configured to receive electromagnetic energy. The device also includes a second antenna configured to separately receive the same electromagnetic energy. The device further includes a radome located in a receiving pathway of the first antenna, where the radome is configured to cause a predetermined phase shift that varies based on an angular position of the receiving pathway. The device includes 1 or more radio receivers to receive the signals independently from the antennas. Additionally, the direction finding device includes a processor configured to determine an angle of arrival of the electromagnetic energy based on a comparison of a phase of the electromagnetic energy received by the first antenna to a phase of the electromagnetic energy received by the second antenna.

Abstract: A method for designing an antenna including defining an operating frequency of an antenna radiating element located within an antenna cavity structure; determining a non-loaded depth of the antenna cavity structure; determining a reduced depth of the antenna cavity structure; determining a reduction factor to reduce the non-loaded depth to the reduced depth; and selecting a dielectric material, at least partially forming a radome structure covering the antenna radiating element, to achieve the reduction factor.

Abstract: An antenna includes an antenna cavity structure that defines an antenna cavity and that has a cavity opening. The antenna also includes an antenna radiating element located within the cavity opening and operable to emit electromagnetic radiation that has a frequency and a wavelength and a radome structure covering the cavity opening. The radome structure includes a dielectric material and defines an antenna window that is transparent to the electromagnetic radiation. Due to the dielectric material of the radome structure, the antenna cavity has a depth less than one-fourth of the wavelength of the electromagnetic radiation and the cavity is filled with a low-dielectric material.

Abstract: An antenna includes an antenna cavity structure that defines an antenna cavity and that has a cavity opening. The antenna also includes an antenna radiating element located within the cavity opening and operable to emit electromagnetic radiation that has a frequency and a wavelength and a radome structure covering the cavity opening. The radome structure includes a dielectric material and defines an antenna window that is transparent to the electromagnetic radiation. Due to the dielectric material of the radome structure, the antenna cavity has a depth less than one-fourth of the wavelength of the electromagnetic radiation and the cavity is filled with a low-dielectric material.

Abstract: An antenna system may include a first antenna, and a second antenna opposite the first antenna, wherein the first antenna and the second antenna are configured to provide omnidirectional coverage.

Abstract: A frequency-selective composite structure includes a laminate panel, and a frequency-selective filter including a plurality of frequency-selective surface elements coupled to an exterior surface of the laminate panel and arranged in a frequency-selective surface pattern, wherein each one of the frequency-selective surface elements includes a nanomaterial composite.

Abstract: An antenna electromagnetic radiation steering system may include an antenna for emitting electromagnetic radiation, and a radome disposed adjacent to and at least partially enclosing the antenna, the radome including a window to pass electromagnetic radiation from the antenna to outside the radome, wherein electromagnetic radiation is directed based on a position of the window relative to the antenna.

Abstract: A frequency-selective composite structure includes a laminate panel, and a frequency-selective filter including a plurality of frequency-selective surface elements coupled to an exterior surface of the laminate panel and arranged in a frequency-selective surface pattern, wherein each one of the frequency-selective surface elements includes a nanomaterial composite.

Abstract: An antenna system may include a first antenna, and a second antenna opposite the first antenna, wherein the first antenna and the second antenna are configured to provide omnidirectional coverage.

Abstract: A composite panel may include a structural first laminate including a first composite material opaque to electromagnetic radiation, the first laminate further including an outer perimeter edge and an inner perimeter edge, and a structural second laminate including a second composite material transparent to electromagnetic radiation, the second laminate being disposed within and physically joined with the first laminate along the inner perimeter edge.

Abstract: An antenna electromagnetic radiation steering system may include an antenna for emitting electromagnetic radiation, and a radome disposed adjacent to and at least partially enclosing the antenna, the radome including a window to pass electromagnetic radiation from the antenna to outside the radome, wherein electromagnetic radiation is directed based on a position of the window relative to the antenna.

Abstract: A compact multi-band antenna structure consisting of overlapping elements formed like tree rings is described. A dipole multi-band antenna includes a first arm having a first conductive cylinder with a predetermined length corresponding to a first frequency and a second conductive cylinder having a predetermined length corresponding to a second frequency positioned over the first conductive cylinder without contact between the first conductive cylinder and the second conductive cylinder. A first end of the first conductive cylinder is in the same plane as and is electrically coupled to a first end of the second conductive cylinder. A second arm is similarly formed. A feed line is coupled to the first and second conductive cylinders and to the cylinders in the second arm. Additional frequencies may be added by similarly stacking additional conductive cylinders. The structure is also applied to monopole, circular, spiral, helical and slot antennas.

Abstract: An integrated driveshaft cover antenna includes a driveshaft cover including a conductive layer and having a generally curved cross-section. The driveshaft cover is hingeably secured and electrically coupled to a helicopter tail boom section to cover a driveshaft access opening. The integrated drive shaft cover includes a dielectric layer including a first surface shaped to conform to a curved outer surface of the driveshaft cover and a second surface opposite the first surface. The first surface of the dielectric layer is positioned over the curved outer surface of the driveshaft cover. The first surface is secured to the curved outer surface of the driveshaft cover. The integrated drive shaft cover includes a slotted patch high frequency (HF) antenna layer having an inner slot and extends a majority of a length of the dielectric layer. The slotted patch HF antenna layer is secured to the second surface of the dielectric layer.

Abstract: An integrated driveshaft cover antenna includes a driveshaft cover including a conductive layer and having a generally curved cross-section. The driveshaft cover is hingeably secured and electrically coupled to a helicopter tail boom section to cover a driveshaft access opening. The integrated drive shaft cover includes a dielectric layer including a first surface shaped to conform to a curved outer surface of the driveshaft cover and a second surface opposite the first surface. The first surface of the dielectric layer is positioned over the curved outer surface of the driveshaft cover. The first surface is secured to the curved outer surface of the driveshaft cover. The integrated drive shaft cover includes a slotted patch high frequency (HF) antenna layer having an inner slot and extends a majority of a length of the dielectric layer.

Abstract: Antennas, integrated driveshaft covers, and methods are disclosed. A particular antenna includes a dielectric layer. The dielectric layer has a first curved surface and a second curved surface opposite the first curved surface. A conductive body has a curved outer surface, where the first curved surface of the dielectric layer is positioned against the curved outer surface. A high frequency (HF) antenna layer is positioned over positioned over the second curved surface of the dielectric layer, where the HF antenna layer is curved to conform to the second curved surface of the dielectric layer. A pair of contacts may be configured to receive an electrical connection for the HF antenna layer. When an HF signal is applied to the pair of contacts, the conductive body interacts with the HF antenna layer to radiate energy.

Abstract: Antennas, integrated driveshaft covers, and methods are disclosed. A particular antenna includes a dielectric layer. The dielectric layer has a first curved surface and a second curved surface opposite the first curved surface. A conductive body has a curved outer surface, where the first curved surface of the dielectric layer is positioned against the curved outer surface. A high frequency (HF) antenna layer is positioned over positioned over the second curved surface of the dielectric layer, where the HF antenna layer is curved to conform to the second curved surface of the dielectric layer. A pair of contacts may be configured to receive an electrical connection for the HF antenna layer. When an HF signal is applied to the pair of contacts, the conductive body interacts with the HF antenna layer to radiate energy.