Multi-arm conformal slot antenna

摘要

An octave bandwidth conformal cavity-backed slot antenna includes a ground plane with a number of different length slits that come together at the central feedpoint. The slit length varies from one-half a wavelength at the highest frequency at which the antenna is to operate for the short side to one wavelength at the highest frequency for the long side, with the proximal ends of the slits having a common feedpoint. Such slot antennas may be arrayed in a quad configuration. Because the trapezoidal envelope of the antenna induces the phase-center to shift with frequency, when two are arrayed with short sides adjacent, the spacing between them results in a phase center from one antenna to the next that is effectively within half a wavelength at all frequencies.

主权项

1. A low radiation cross section wide bandwidth conformal cavity-backed slot antenna having a wide 2:1 instantaneous bandwidth, comprising:
a cavity-backed multi-arm slot antenna having a single cavity in back of a ground plane, a single central feedpoint and a number of different length directly driven pairs of spaced apart opposed slits in said ground plane, each pair of opposed slits forming an actively driven dipole, said opposed spaced apart slits being free ended at the distal ends thereof, outwardly width-wise tapered, wide and connected across proximal slit ends to said single central feed point that forms a center feed for the associated dipole, said slits comprising pairs of opposed unfolded arms characterized by short slits and long slits, the distal ends of said short slits and said long slits defining a trapezoidal envelope, the shortest distance between said short slits and said long slits being no more than one-quarter wavelength at the highest frequency at which said antenna is to operate, the overall length of said long slits being twice that of the overall length of said short slits, such that said wide 2:1 instantaneous bandwidth with low radiation cross section for a cavity-backed antenna is obtained by said tapering, said wide slits and said dimensions.