A low profile broadband wide scan phased array

The design of a low profile, broadband element, with wide scan property and suitable for use in small phased arrays, is presented. The radiator is a dual-probe, capacitive-fed patch with a parasitic element and backed by a metallic cavity. The cavity is filled with rohacell foam and the patches are supported by layers of this foam. Such a radiator designed for a maximum scan of 45° in the E-plane is shown to have a frequency ratio greater than 2.35:1 or bandwidth > 81% and with an active scan VSWR of 2:1. The broadband property is obtained through capacitive feeding with two large stepped probes in a balanced configuration. Further, the element is compact, with a height at less than 0.27¿_C including the balun feed where ¿_C is the wavelength at mid-band.