A 2-Bit Electronically Planar Reconfigurable Array Antenna With 2-D Beam-Scanning Capacity Using Hybrid Phase Control Method

A 2-bit electronically planar reconfigurable array antenna (PRAA) at the
Ku
-band is presented in this letter. The proposed PRAA element employs the hybrid phase control method to realize the reconfiguration of its radiation structure and feeding structure. The radiation structure is designed as an O-slot radiation patch integrated with two p–i–n diodes to obtain a 1-bit phase quantization. To obtain the 2-bit phase control ability, a digital phase shifter with two p-i-n diodes is integrated into the feeding structure to obtain additional 90° phase shifting. Then, a 4 × 4-element subarray is designed and simulated, which is fed by using an asymmetric 16-way stripline feeding network. To realize 2-D beam scanning, an 8 × 8-element PRAA prototype is fabricated and measured, which is composed of four subarrays stitched together. The measured gain of the pencil beam is 20.8 dBi at 12.2 GHz with an aperture efficiency of 60.0%, while the 3 dB gain bandwidth is 13.9% (11.4–13.1 GHz). The measured results verify that the proposed PRAA has good 2-D beam scanning capability within ±45°. In addition, the height of the PPRA prototype is only 0.3
λ
₀
, which indicates this design has a highly integrated, planar, low-profile structure.