We present an analysis of cylindrical connected array unit cells. Analytical expressions of the active input impedance are derived for both connected slots and dipoles in the presence of a backing reflector. The dipoles and slots can be oriented along the circumferential or longitudinal directions in cylindrical coordinates. A study on the variation of impedance as a function of the radius of curvature is presented. Difficulties with the numerical implementation of high-order cylindrical Floquet modes are discussed. To solve these issues, a method is proposed to approximate the higher-order mode component of the cylindrical array impedance with the one of the equivalent planar geometry. This approach is justified by the observation that the reactive energy associated with the unit cell is weakly dependent on the curvature.

Multi-beam systems are a key technology for the high-speed links of the next-generation communication standards. Due to the stringent space constraints for allocating antennas on a platform, it is of paramount importance to assess - with respect to the physical size - the multi-beam performance of the antenna in terms of the maximum number of simultaneous orthogonal beams. This is done by resorting to the concept of the observable field, which is here extended to planar domains. Then, this concept is used to assess the multi-beam performance of a wideband phased array prototype developed for mobile communications. The Signal-to-Interference Ratio (SIR), computed from the measured radiation patterns of the prototype, is analyzed versus the frequency and the number of beams and compared to the benchmark case of an ideal antenna radiating the observable field.

We present a systematic approach to include the effects of dielectric slabs in artificial dielectric layers (ADLs). Typical implementations of ADLs consist of layers of sub-wavelength metal patches supported by either dielectric slabs or thin dielectric films bonded onto foam spacers. The presence of dielectrics in the proximity of the metal layers affects the equivalent layer capacitance and thus must be accurately taken into account for the modeling and design of the ADLs. The proposed procedure allows to derive an analytical expression for the effective permittivity of each capacitive layer that depends on the dielectric layers in the vicinity of the metal. The equivalent layer capacitance can be then included in the ADL equivalent transmission line model, which can be used, for instance, for the design of matching structures in ultra-wideband arrays.