A Switchable S-/C-Band Antenna Array With Dual Polarization and Modularity

A switchable S-/C-band antenna array is presented with dual polarization and modularity. A 2 x 2 S-band antenna array can be reconfigured into a 4 x 4 C-band antenna array within the same physical aperture. A narrow ground strip inside the slot-ring antenna is used to reduce the mutual coupling between antenna elements and suppress the null in the radiation patterns in the C-band array. In addition, the vertical coaxial-to-microstrip transition allows for feeding the antenna array from behind the ground plane, making it modular. Dual polarization capability is achieved in each band. This antenna array shows 64.3% and 66.7% fractional bandwidth with 8.4 and 14.3 dBi gain in the S- and C-band operating states, respectively. The isolation between different antenna ports, radiation patterns at different frequency points, and input third-order intermodulation product of the antenna is measured. A triangular lattice is implemented for the S-band array to minimize the physical spacing between the antenna elements, and therefore enable beam steering to large angles.