A novel element for broadband reflectarray antennas

A novel broadband reflectarray element composed of two ellipse-like rings is presented. Compared with those conventional broadband elements, the proposed element can realize a broader bandwidth, which means a more similar behavior for the phase curves at different frequencies. In order to validate the proposed design and evaluate its performance, a prime-focus 69-element reflectarray with this type of element has been designed and fabricated. The highest measured gain is about 20 dB at the center frequency of 11 GHz, and a relative bandwidth of 36.4% (9-13 GHz) is achieved within 2 dB gain variations. All experimental results show that the proposed element is superior in bandwidth performance, which can be widely used in broadband applications.