Concentric circular antenna array (CCAA) has interesting features over other array configurations.A uniform arrangement of elements is assumed where the interelement spacing is kept almost half of the wavelength and the array parameters such as the steering matrix and gain are determined.The array performance such as beam power pattern, sidelobe level and beamwidth are discussed in two cases of central element feeding.The two cases are compared showing the reduction in the sidelobe level to more than 20 dB in the case of central element feeding without extra signal processing especially for smallsized arrays that have smaller number of elements and rings.
2. Owsley, N. L., Array Signal Processing, S. Haykin (ed.), Prentice- Hall, Englewood Cliffs, NJ, 1985.
3. Peterson, P.M., et al., "Multimicrophone adaptive beamforming for interference reduction in hearing aids," Jour. of Rehab. R&D, Vol. 24, 1987.
4. Compton, R. T., An adaptive array in a spread-spectrum communication system, Proc. IEEE, Vol. 66, No. 3, 289-298, 1978.
5. Kak, A. C., Array Signal Processing, S.Haykin (ed.), Prentice- Hall, Englewood Cliffs, NJ, 1985.
6. Fletcher, P. and P. Darwood, Beamforming for circular and semicircular array antennas for low-cost wireless lan data communications systems, IEE Proc. Microwaves, Vol. 145, No. 2, 153-158, 1998.
7. Bogdan, L. and C. Comsa, Analysis of circular arrays as smart antennas for cellular networks, Proc. IEEE Int. Symp. Signals, Vol. 2, No. 7, 525-528, 2003.
8. Chan, S.C.and C.K.S.Pun, On the design of digital broadband beamformer for uniform circular array with frequency invariant characteristics, Proc. IEEE ISCAS'02, Vol. 1, No. 5, 693, 2002.
9. Li, Y., K.C.Ho, and C.Kw an, A novel partial adaptive broad-band beamformer using concentric ring array, Proc. IEEE ICASSP'04, No. 5, 177, 2004.
10. Wan, J. X., J. Lei, and C.-H. Liang, "An efficient analysis of largescale periodic microstrip antenna arrays using the characteristic basis function method," Progress In Electromagnetics Research, Vol. 50, 61-81, 2005.
11. Mouhamadou, M., P.Armand, P.V audon, and M.Rammal, "Interference supression of the linear antenna arrays controlled by phase with use of SQP algorithm," Progress In Electromagnetics Research, Vol. 59, 251-265, 2006.
12. Sanyal, S.K., Q.M.Alfred, and T.Chakra varty, "A novel beamswitching algorithm for programmable phased array antenna," Progress In Electromagnetics Research, Vol. 60, 187-195, 2006.