PCB-Based TRX AESA for Ka-band In-Flight Connectivity

We developed an Active Electronically Steered Array (AESA) based on a PCB and silicon RF-IC for Ka-band In-flight-connectivity (IFC). One of the goals of the AESA for IFC is to achieve low SWaP-C (Size, Weight, Power consumption and Cost) in an array of several thousand elements. We consider the wide-angle beam steering capability as an important factor to achieve low SWaP-C, and propose an AESA that combines multiple PCBs to achieve it. This enables beam steering of up to 80 degrees in circular polarization (RHCP/LHCP) in the 3.5 GHz band. In addition, a compact PCB filter capable of 30 dB harmonic suppression between the antenna element and RF-IC is realized. We also studied the radiation characteristics of the AESA when mounted on an aircraft model, and estimated the effect of the aircraft fuselage on the radiation characteristics and the radiation level to the ground. Finally, we designed and evaluated a 1,024-element Transmitting AESA and a 256-element Receiving AESA. As a result, we obtained a beam steering angle characteristic of the Transmitting AESA with an envelope of 1.05 power of the cosine. The beamforming characteristics of the Receiving AESA were also obtained as designed. Based on the results obtained in this development, AESAs can be designed to meet various IFC system requirements by array expansion.