Uniform concentric circular array (UCCA) is CCAA where all
the elements in the array are uniformly excited and the interelement
spacing in individual ring is kept almost half of the wavelength. The
sidelobe level in the UCCA drops to about 17.5 dB, especially at large
number of rings with uniform excitation. UCCA has high directivity
but it usually su®ers from high sidelobe level [6]. Central element
existence in UCCA reduces the sidelobe level while minor increase in
the beamwidth [6].