X-Band Reflectarray Antenna With Switching-Beam Using PIN Diodes and Gathered Elements

An electronically switching-beam reflectarray antenna to be used in X-band has been designed, manufactured and tested, using PIN diodes as switching device. The antenna has 244 elements arranged in a circular aperture. With the aim of saving electronic devices and reducing both manufacturing complexity and cost, the phase control has been implemented at sub-array level, using aperture-coupled patches gathered by pairs to a common delay line. The antenna was designed to switch the beam between +/- 5 degrees, in a scanning plane tilted 18.3 degrees with respect to the YZ plane. Each state was obtained by forward biasing one half of the diodes, while the other half remains in reverse biasing. A third state with the beam pointing to 0 degrees was obtained when all the diodes are in reverse biasing. The concept has been demonstrated by manufacturing and testing a breadboard. The measured radiation patterns fulfill the design requirements.