Millimeter-Wave Single-Layer Wideband High-Gain Reflectarray Antenna With Ability of Spatial Dispersion Compensation

The spatial dispersion significantly limits the operating bandwidth of a large-aperture reflectarray antenna. To achieve a wideband high-gain reflectarray antenna, a design method is proposed based on the spatial dispersion compensation concept. By introducing different resonant structures in reflectarray elements, each element has the ability to track the desired frequency-phase response, which means that the spatial dispersion of the large-aperture reflectarray antenna can be compensated by the phase dispersion of the reflectarray element over the entire frequency band. Thus, a wideband highgain reflectarray antenna can be realized by the use of singlelayer elements. As an example, a center-fed reflectarray antenna with a diameter of 354 mm (35.4λ
₀
at 30 GHz) and a focal length to diameter ratio of 0.97 is designed and fabricated. The measured maximum gain of the prototype reflectarray antenna is 37.8 dBi with a 1 dB bandwidth of 26.7%, i.e., from 26.5 to 34.5 GHz. Compared with other high-gain single-layer reflectarray antennas, this type of antenna presents better performance.