A Low-Sidelobe Partially Overlapped Constrained Feed Network for Time-Delayed Subarrays
AIR FORCE RESEARCH LAB HANSCOM AFB MA SENSORS DIRECTORATE
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Completely overlapped space-fed subarrays have been shown to provide sufficient pattern control to enable modestly wide-band arrays using time delays at the input to each subarray and phase shifters at the array face. These configurations are bulky, but have been proposed for space-based use as well as for certain ground-based applications that do not have severe volume constraints. Other applications for space-based and airborne radar require much more compact, constrained array feed networks, but until now there have been few appropriate constrained networks for inserting time delay at the subarray ports without causing high sidelobes. This paper describes one such network that, at the outset, provided far lower sidelobes than the usual contiguous subarrays, but retained closely spaced high lobes near the main beam. This paper presents a synthesis procedure that alters the subarray pattern and reduces nearly all array sidelobes to levels determined by tolerance errors. Several examples are presented that synthesize sidelobes at -40 dB. The resulting network operates over 70 to 80 of the maximum theoretical bandwidth.
- Electrical and Electronic Equipment
- Radiofrequency Wave Propagation