ANALYSIS OF MUTUAL COUPLING IN A CAVITY-BACKED COAXIAL ARRAY OF ANNULAR-SLOT ANTENNAS

The problem of mutual coupling in a coaxial array of annular-slot ante nnas is formulated in terms of a magnetic-field integral equation (MFI E). The MFIE is solved numerically, under the assumption of narrow slo t width, using a moment method with a Fourier basis and point matching . The operation of the array under multiport excitation is analysed, a nd an impedance matrix representation of the multiport antenna is calc ulated. Results predicted by the theory are shown to be in good agreem ent with experimental measurements on a two-port, two-element coaxial annular-slot array.