Abstract: A radar antenna suitable for a drone is provided, which is able to compensate for the agility of drone motion. The radar antenna contains a sandwich of two printed circuit boards between three conductive plates. A first printed circuit board comprises a preferably circular array of first antenna elements such as dipoles. A second printed circuit board, parallel to the first printed circuit board, comprises an array of second antenna elements. One of the array of first antenna elements and the array of second antenna elements is an array of transmission antenna elements and the other an array of reception antenna elements. The first printed circuit board is located below the second printed circuit board. Three conductive plates are used to shape the antenna patterns from the antenna elements so that the main lobes of the antenna patterns are directed obliquely downwards and the antenna patterns from the different array at least partly overlap, suppressing vertical side lobes.

Abstract: Systems and methods for protecting an airborne platform against collisions are provided. One system includes FMCW radar sensors including transmitting antennae, means for receiving signals from echoes and for processing and digitizing same, and means for sending a central unit data representing said digital signals via a dedicated point to point link. The central unit includes means for processing said data to detect obstacles, means for calculating parameters for each obstacle including its radial velocity, distance range and azimuth, and means to transmit an avionic system of said platform data representing said detected obstacles and parameters. The system further includes means for guaranteeing that said emitted signals are shifted in time to create a shift in frequency guaranteeing that the radar sensors operate in the whole frequency band without perturbing each other.

Abstract: Systems and methods for protecting an airborne platform against collisions are provided. One system includes FMCW radar sensors including transmitting antennae, means for receiving signals from echoes and for processing and digitizing same, and means for sending a central unit data representing said digital signals via a dedicated point to point link. The central unit includes means for processing said data to detect obstacles, means for calculating parameters for each obstacle including its radial velocity, distance range and azimuth, and means to transmit an avionic system of said platform data representing said detected obstacles and parameters. The system further includes means for guaranteeing that said emitted signals are shifted in time to create a shift in frequency guaranteeing that the radar sensors operate in the whole frequency band without perturbing each other.

Abstract: An electronic circuit comprising a power limiter circuit. The power limiter circuit comprises a plurality of cascaded transmission line sections, each transmission line section comprising a series arrangement of at least one diode and a dissipative element for absorbing excess input signal power connected in series. The series arrangement is connected between an output of the section and effective ground, a number of diodes connected in series in the series arrangements of the sections decreases with position of the section from an input of the power limiter to an output of the power limiter by steps of one or more diodes at least at part of the sections.

Abstract: An electronic circuit comprising a power limiter circuit. The power limiter circuit comprises a plurality of cascaded transmission line sections, each transmission line section comprising a series arrangement of at least one diode and a dissipative element for absorbing excess input signal power connected in series. The series arrangement is connected between an output of the section and effective ground, a number of diodes connected in series in the series arrangements of the sections decreases with position of the section from an input of the power limiter to an output of the power limiter by steps of one or more diodes at least at part of the sections.