Abstract: An antenna is described which includes first, second, and third conductive layers and a first and second laminate to separate the layers. The laminates are configured with plated through holes to provide contact between the first and third layers, the holes defining antenna cavities, the second conductive layers being the antenna. A plurality of slots in the first conductive layer align within the defined antenna cavities, further defining the antenna cavities for the second conductive layer.

Abstract: A radar altimeter is described which includes a transmitter for transmitting a radar signal, a receiver for receiving the reflected radar signal, and at least one antenna coupled to one or both of the transmitter and receiver. The altimeter also includes a forward facing millimeter wave (MMW) antenna configured to move in a scanning motion and a frequency up/down converter coupled to the MMW antenna, the transmitter, and the receiver, and a radar signal processor. The converter up converts a frequency received from the transmitter to a MMW frequency for transmission through the MMW antenna, and down converts frequencies received to a radar frequency which are output to the receiver. The radar signal processor controls scanning motion of the MMW antenna, processes signals received at the antenna for a portion of the scanning motion, and processes signals received at the MMW antenna for other portions of the scanning motion.

Abstract: An antenna is described which includes first, second, and third conductive layers and a first and second laminate to separate the layers. The laminates are configured with plated through holes to provide contact between the first and third layers, the holes defining antenna cavities, the second conductive layers being the antenna. A plurality of slots in the first conductive layer align within the defined antenna cavities, further defining the antenna cavities for the second conductive layer.

Abstract: A method for determining a position of a doppler radar target in aircraft body coordinates is described. The method includes calculating values for doppler circle equations, in doppler coordinates, based upon a range to the target, a vehicle velocity, and a center frequency and bandwidth of a doppler swath filter. Further, an interferometric circle in body coordinates is calculated based upon a range to the target, and an interferometric angle. The doppler circle equations are transformed into body coordinates utilizing received pitch, roll and yaw information. Finally, an intersection of the interferometric circle equations with the transformed doppler circle equations is calculated, the intersection being the position of the target in body coordinates.