A Double-Layer Wideband Transmitarray Antenna with Compensation Elements

A double-layer wideband transmitarray antenna with small compensation elements is proposed. The double-layer transmitarray antenna consists of 441 standard elements and 128 small elements. Standard elements have two freedom degrees, which can achieve a 360° phase shift range. And small elements placed at the intersection of the four standard elements is able to generate an approximate 90° phase shift range. The simulation results show that the phase shift curve of the small unit is very flat with wide bandwidth. Therefore, the addition of small elements can not only increase the gain but also increase the bandwidth. The array is designed, manufactured and testing. The experimental data is in good agreement with the simulation. The proposed transmitarray achieves a gain of 29.5 dB at 34 GHz, with an aperture efficiency of 41% and 1dB gain bandwidth of 10.3% (32.1GHz-35.6GHz). The small elements can also be added to other similar lens antenna to enhance the gain and bandwidth.