On the Design of a Dual Band Hybrid-Chebyshev Collinear Dipole Antenna Array

The arrangement of a mast-mounted antenna array with a comer reflector is considered. The method of moments (MoM) in a wire grid model is used and a suitable optimization procedure is applied. The structure of each element of the array as a set of an active and a parasitic dipole makes the array resonant in two frequency bands. Due to the constraints for high power gain and low SLL the array is designed as a simple broadside Chebyshev one. The presence of a 120/spl deg/ comer reflector changes the pattern and makes the array a hybrid-Chebyshev one with approximately the same SLL. The distance of the array from the corner of the reflector and the spacing between active and parasitic dipoles are critical for the HPBW and the resonance in the two frequency bands. Two different types of antennas with 60/spl deg/ and 120/spl deg/-HPBW in the horizontal plane for possible mobile applications are studied. The optimization procedure gives the important antenna pattern and impedance. To meet with success the appropriate specifications it is necessary to start with a Chebyshev array having more exacting constraints. From the impedance matrix, and the dipole current excitation the information for the feed network are taken. The whole work of the design is given in a form useful for mobile communication applications. In the examples several, interesting cases are analytically presented.