Abstract: An active array antenna, which may be used for radar, includes antenna elements (antelements) supported in a two-dimensional array. The fronts of the elements are protected by a cover. In order to allow easy repair, each column of antelements is associated with a slide-in carrier which simultaneously mates with all antelements of a column. Each carrier has a transmit-receive (TR) module for each antelement with which it mates, and a column beamformer. Each carrier also has logic modules and power supplies for the TR modules. The total width of each slide-in carrier with its TR modules, beamformer, logic and power supplies, is less than or equal to the column-to-column spacing. Each carrier can be slid out from the rear to expose all the active components for each column of antelements, so maintenance can be performed without environmental exposure.

Abstract: A short horn antenna (10) adapted for array use includes a rectangular waveguide with broad upper (12) and lower (14) walls and narrow side walls (16, 18), defining a radiating aperture (20) and a feed end closed off by a shorting plate (22). A stepped upper ridge (26) has a slot (50) adjacent the shorting plate, and a shorter stepped lower ridge (46) has a corresponding slot. An unbalanced transmission line (75) extends through the shorting wall, and the smaller conductor (76) extends into the waveguide as an electric probe (60). The probe includes a first portion (64), extending parallel to the waveguide axis (8) and into the slot in the upper ridge. The probe (60) also includes a second portion (66) extending at an angle (90.degree.) relative to the first portion (64) of the probe (60).

Abstract: An antenna array (10) includes a plurality of antenna elements (12), each of which is associated with a transmit-receive TR module (14). The antenna elements and their associated TR modules are grouped into sets, which in the illustrated embodiment are sets of four. Each set of four TR module/antenna elements is associated with one phase and gain controller (18.sub.X), which is part of a distributed phase and gain controller. The beam direction is commanded by a central radar control computer (RCC) (22), which transmits beam direction and other information to all the separate phase/gain controllers. Each separate phase/gain controller accesses local memory to obtain data relating to the location within the array of those antenna elements which it controls. Each phase/gain controller then calculates the necessary phase shift for each antenna element it controls, taking into account the phase and gain errors associated with the TR module associated therewith.

Abstract: A monopulse antenna array arrangement includes a transmit-receive processor (TR Proc) associated with each antenna element. Each TR Proc has a port associated with the radiating element and at least two further ports, one for a sum beamformer and another for a difference beamformer. Within each TR Proc, a switching arrangement allows transmitter signal to flow through a phase shifter and transmit amp during transmission, and allows received signal to flow through a low-noise amp and the same phase shifter on reception. Each TR Proc includes a coupling arrangement with a second phase shifter and a second output port, adapted to be coupled to a difference beamformer during reception.

Abstract: A printed circuit dipole monopulse antenna includes a planar printed circuit substrate having a plurality of dipole antennas and a feed network including a sum and difference hybrid printed thereon. Low sidelobe and monopulse operation are provided along one axis of the antenna.