High Gain Ka-Band Data Link Antennas with Wide-Field-of-Regard (WFOR)

ABSTRACT: As airborne sensors become more prolific and more sophisticated, the amount of data they are able to produce overwhelms the current ability to offload that data based on the meager performance of ground station terminals. A high gain antenna supporting Ka-Band sensor data offload and Command and Control Uplink is required. Gimbaled reflectors are the standard choice, but their design requires very sophisticated gimbals and control algorithms. Phased arrays have been used to simplify the mechanical steering problem as well as reduce the height, but they are expensive, less efficient and suffer from scan loss at extreme angles from boresight. FIRST RF proposes a novel two-axis mechanically steered aperture system for the Wide Field-of-Regard (FOR) High Gain Ka-Band Data Link. This concept offers reliability and performance in a compact package that is compatible with ground-based fixed or mobile platforms. The proposed beam waveguide system enables precision tracking without requiring beam motion, such as with sequential lobe (or conical scanning) systems. To control risk to the program and the overall design, FIRST RF has budgeted to produce a prototype reflector based on the proposed design during the Phase I program. BENEFIT: The proposed antenna is orders of magnitude lower cost than phased arrays, with no scan loss. It is moderately lower cost than conventional two axis gimbaled reflectors, due to one key design parameter that influences the selection of motors: whereas conventional gimbaled reflectors have a center of mass that is out over the pedestal, the proposed antenna has a center of mass about the azimuth center of rotation, implying that much less sophisticated motors with lower torque and mass requirements can be used to drive the assembly. Further, our approach employs a stationary feed which does not require rotary joint. This substantially reduces cost compared to other reflector-based approaches. The proposed system maintains a compact size and footprint ideal for ground operations. The total swept volume of this design is not much larger than the swept volume of the diameter of the aperture .