An antenna system for an aircraft, comprising one or more antennas configured and arranged on the aircraft to provide a downlink rate of at least one Gbps, the one or more antennas permitting a base cell tower placement with a diameter of at least 60 km, the one or more antennas being configured and arranged to support multiple data streams simultaneously, the one or more antennas supporting multiple polarizations, the one or more antennas having a high gain over most of a hemisphere around the one or more antennas of −85°≤θ≤85°, 0°≤φ≤360°.

A reconfigurable antenna includes a first antenna and a second antenna. The first antenna is an omnidirectional antenna, and the second antenna surrounds the first antenna. The second antenna includes a plurality of antenna element groups. Each antenna element group includes a transmission cable, a switch, a first antenna element, and a second antenna element. The transmission cable is connected to the first antenna element and the second antenna element. The transmission cable is connected to a feedpoint. The switch is connected to a first point and a second point on the transmission cable. A sum of a length of antennas and transmission cables in an antenna element group is slightly greater than ½ wavelength (λ.sub.1), where λ.sub.1 is a wavelength of an electromagnetic wave on an operating frequency of the first antenna.

An antenna system is provided that can include a plurality of parasitic elements connected to and extending from a ground plane, wherein each of the plurality of parasitic elements can be oriented at a common pitch angle, wherein each of the plurality of parasitic elements can be positioned at a uniform distance from a center of an antenna disposed on the ground plane, and wherein a respective length of each of the plurality of parasitic elements, the common pitch angle, and/or the uniform distance can be optimized so as to broaden a beamwidth of a radiation pattern produced by the antenna.

An antenna assembly includes a driven element, a first set of antenna elements disposed a first distance from the driven element such that each element of the first set of antenna elements is equidistant from adjacent elements of the first set of antenna elements, and a second set of antenna elements disposed a second distance from the driven element such that each element of the second set of antenna elements is equidistant from adjacent elements of the second set of antenna elements, the second distance being larger than the first distance. The antenna assembly includes or is operably coupled to a selector module configured to select one element of the first set of antenna elements as a selected director, and select one element of the second set of antenna elements as a selected reflector by effectively shortening a length of the selected director and effectively lengthening the selected reflector.

A method for hybrid RF beamforming comprising: providing an antenna structure which comprises: a driven element, parasitic elements configured to couple/decouple a linearly polarized radiation pattern and arranged around the driven elements, a feed system comprising four ports that are 90 degrees out of phase with each other and are connected to the driven element, RF switches electrically connected to the parasitic elements and the four ports, and a controller operatively connected to the RF switches; selectively attenuating an output of each of the four ports with the controller according to a stored configuration, which is stored in a memory, by changing the four ports' respective phase or attenuation; and selectively changing a loading of each parasitic element by activating each parasitic element's corresponding RF switch with the controller according to the stored configuration so as to produce a desired null/beamforming of a main RF beam.

A system and method reconfiguring an antenna for reducing and/or eliminating the effects of multipath on a phase-based measurement system. The method includes steering an antenna unit into a first direction to cause the antenna unit to generate a first constant tone (CT) signal based on a plurality of multipath signals. The method includes performing a phase measurement on the first CT signal to generate a first phase measurement value. The method includes steering the antenna unit into a second direction to cause the antenna unit to generate a second CT signal based on the plurality of multipath signals. The method includes performing a phase measurement on the second CT signal to generate a second phase measurement value. The method includes determining a change in multipath interference at the antenna unit among the plurality of multipath signals. The method includes re-steering the antenna unit into the first direction.

An electronically steerable parasitic array (ESPAR) antenna system that includes an ESPAR antenna, a GPS receiver, a GPS low-noise amplifier, a power detector module, and a central processing unit. The GPS receiver is connected to the ESPAR antenna as a separate component. The GPS low-noise amplifier strengthens a signal to propagate through the transmission line and operates in the L1 and L2 GPS bands. The power detector module provides additional amplification for noise quantification. The power detector receives an RF power level and converts the RF power level into a DC voltage output. The central processing unit includes memory that is capable of storing the DC voltage output from the power detector.

A radar antenna for a fill level measurement device is provided that includes at least one carrier plate and at least two antenna elements that are arranged on the carrier plate and are configured to transmit and/or to receive a radar signal, wherein each of the antenna elements includes a waveguide configured to direct the radar signal, wherein an interior volume of each waveguide is at least partially filled with a dielectric, the antenna elements being arranged at a distance from one another that is less than or equal to a wavelength of the radar signal.

An antenna system is provided that can include a plurality of parasitic elements connected to and extending from a ground plane, wherein each of the plurality of parasitic elements can be oriented at a common pitch angle, wherein each of the plurality of parasitic elements can be positioned at a uniform distance from a center of an antenna disposed on the ground plane, and wherein a respective length of each of the plurality of parasitic elements, the common pitch angle, and/or the uniform distance can be optimized so as to broaden a beamwidth of a radiation pattern produced by the antenna.

Disclosed is an array antenna comprising a plurality of array elements. The plurality of array elements are formed as a coupler including a central element and peripheral elements configured to surround the central element; each of the central element and the peripheral elements is formed as a waveguide; and the peripheral elements are excited in higher-order modes using coupling slots to form a beam pattern through an electric field distribution of the central element and the peripheral elements.