Abstract: An exemplary receive antenna having a conductive surface. The conductive surface includes an aperture configured to operate as a slot antenna, and one or more amplifiers or buffer amplifiers is electrically connected across the aperture. At least one feed is connected between the one or more amplifiers and the aperture. An input impedance ZB of each of the one or more amplifiers at the at least one feed location is lower than 0.5× an impedance of the aperture ZA at a first resonance frequency.

Abstract: An exemplary receive antenna having a conductive surface. The conductive surface includes an aperture configured to operate as a slot antenna, and one or more amplifiers or buffer amplifiers is electrically connected across the aperture. At least one feed is connected between the one or more amplifiers and the aperture. An input impedance ZB of each of the one or more amplifiers at the at least one feed location is lower than 0.5× an impedance of the aperture ZA at a first resonance frequency.

Abstract: Tethered Unmanned Aircraft Antenna utilizing a Vertical Take Off and Landing (VTOL) Unmanned Aerial System (UAS) which may be provided by quadcopter drone (for example) constrained by a tether connected at one end to a maritime or land-based platform, the tether also being used as a RF antenna. The tether is capable of transmitting DC power to the UAS or drone at a desired antenna height and simultaneously supports RF transmission power with the help of a DC power isolation circuit. The tether is desirously lightweight and corona resistant.

Abstract: An exemplary receive antenna having a conductive surface. The conductive surface includes an aperture configured to operate as a slot antenna, and one or more amplifiers or buffer amplifiers is electrically connected across the aperture. At least one feed is connected between the one or more amplifiers and the aperture. An input impedance ZB of each of the one or more amplifiers at the at least one feed location is lower than 0.5× an impedance of the aperture ZA at a first resonance frequency.

Abstract: A drive circuit with predistortion. In some embodiments, a system includes a signal input, a predistortion circuit, and an amplifier circuit. The predistortion circuit may be operatively coupled to the signal input and to the amplifier circuit and configured to modify a radio frequency (RF) signal received at the signal input to cause the amplifier circuit to drive, into a load connected to the amplifier circuit, a current that is substantially a replica of the input signal.

Abstract: Tethered Unmanned Aircraft Antenna utilizing a Vertical Take Off and Landing (VTOL) Unmanned Aerial System (UAS) which may be provided by quadcopter drone (for example) constrained by a tether connected at one end to a maritime or land-based platform, the tether also being used as a RF antenna. The tether is capable of transmitting DC power to the UAS or drone at a desired antenna height and simultaneously supports RF transmission power with the help of a DC power isolation circuit. The tether is desirously lightweight and corona resistant.

Abstract: A transmitting circuit. In some embodiment, the transmitting circuit includes a slot antenna and an amplifier. The slot antenna may include a slot in a conductive sheet, and it may have a first resonant frequency, the first resonant frequency being within 20% of a slot frequency which is between a first frequency corresponding, in a first volume, to a wavelength twice the length of the slot, and a second frequency corresponding, in a second volume, to a wavelength twice the length of the slot. The amplifier may be connected to the slot through a connection including a conductive path, between the amplifier and the slot, having a length less than 0.2 times the length of the slot. The magnitude of the output impedance of the amplifier may be less than 0.25 times the magnitude of the impedance of the slot antenna at a first resonant frequency.

Abstract: A Continuous Phase Frequency Shift Keying modulator provided to receive a series of binary symbols having a predetermined repetition period, and generate a series of sinusoidal signals comprising in sequence: a first sinusoidal signal with a first frequency in response to each received binary symbol having a first binary value; and a second sinusoidal signal with a second frequency in response to a received binary symbol having a second binary value, where the lowest of the first and second frequencies is larger than or equal to a third of the symbol rate; wherein the sinusoidal signals are shortened or lengthened with respect to the binary symbol they respond to, such that each first sinusoidal signal comprises an integer number of half periods of said first frequency and each second sinusoidal signal comprises an integer number of half periods of said second frequency.

Abstract: An active artificial magnetic conductor comprising an array of unit cells, each unit cell comprising an electrically conductive patch that is connected with an electrically conductive patch of neighboring unit cell in a column of unit cells using a non-Foster negative inductor and having RF isolating plates or walls between rows of unit cells. These isolating plates or walls eliminate undesirable cross coupling between the non-Foster negative inductors. The electrically conductive patches may be formed by metallic patches preferably arranged in the 2D array of such patches. Each patch preferably has a rectilinear shape.

Abstract: An antenna comprises a dielectric material having first and second surfaces, a discrete lens array operatively coupled to the first surface, and at least one broadside feed antenna operatively coupled to the second surface.

Abstract: An antenna comprises a dielectric material having first and second surfaces, a discrete lens array operatively coupled to the first surface, and at least one broadside feed antenna operatively coupled to the second surface.