Bandwidth enhancement technique for a square waveguide phased array element

This paper presents work on extending the bandwidth of a square waveguide by exploiting the symmetry properties of the modes. The approach is to place dielectric loading inside the square waveguide to separate the cutoff frequencies of the TE/sub 10/ and TE/sub 20/ modes. The TE/sub 11/ and TM/sub 11/ modes are suppressed using mode filters. This novel approach referred to as the crossed septum dielectric loaded waveguide (CSW) extends the usable bandwidth of a square waveguide from 1.414:1 to 2.2:1. The resulting structure is a candidate radiating element for a high power, dual polarized phased array that offers graceful degradation over this extended frequency range.