On the Design of a Dual-Band,Switched-Beam Antenna Array with Constant Excitation Coefficients

A new technique is proposed for the design of dual-band, switched-beam, wire antenna arrays, using the method of genetic algorithms (GA's). The main goal of the proposed technique is the preservation of constant excitation coefficients during operation at different frequency bands. This is accomplished by jointly optimizing the array's technical characteristics for operation at both frequency bands, while properly exploiting mutual coupling between array elements. Numerical results are presented in the case of a uniform, eight-element circular array, with radiation characteristics specified for the 2.4–2.4835 GHz and 3.4–3.8 GHz frequency bands, and excellent agreement to design considerations is demonstrated. Stelios A. Mitilineos was born in Athens, Greece, in 1977. He received the Diploma in electrical and computer engineering from the National Technical University of Athens (NTUA) in October 2001. He is currently working toward the Ph.D. degree in electrical engineering at the same university. His main research interests are in the area of antennas and propagation, smart antennas and mobile communications, MIMO systems and microwave components. Christos N. Capsalis was born in Nafplion, Greece, in 1956. He received the Diploma in electrical and mechanical engineering from the National Technical University of Athens (NTUA) in 1979 and the B. S. degree in economics from the University of Athens in 1983. He obtained the Ph.D. degree in electrical engineering from NTUA in 1985. He is currently a Professor at the department of Electrical and Computer Engineering in NTUA. His current scientific activity concerns satellite and mobile communications, antenna theory and design, and electromagnetic compatibility.