EXCITATION OF A PERIODIC CYLINDRICAL MICROSTRIP N-ELEMENT ANTENNA ARRAY

We consider the problem of excitation of a periodic cylindrical microstrip antenna array which consists of N elements placed periodically in the azimuthal plane on the surface of a dielectric substrate. Each element is an array of M patches having the rectangular-cylindrical shape. Each patch is fed by a rod which is approximately modeled by a charged filament of finite length. An integral equation for the surface current on the patches is formulated and solved by the method of moments in the spatial domain. Far-field patterns of the antenna are calculated for different values of N and M at the resonant frequencies. It is shown that a two-frequency N-lobe antenna having two different far-field patterns at two different resonant frequencies can be developed.