A planar broadband substrate-integrated waveguide 1 x 2 array antenna for the Ka-band wireless communication

This article proposes a Ka-band substrate integrated waveguide (SIW) quasi-Yagi array antenna with the advantages of thinness, compactness, wide bandwidth, and higher gain. Analyzing the microstrip-to-SIW transition structure to confirm that the designed structure provides the best performance, the optimum reflectance coefficient bandwidth can be obtained. With the optimized rectangular etched slot structure at the antenna end, the impedance matching can be tuned to improve the bandwidth. The designed array antenna is fabricated and measured for verification. The substrate is based on Al2O3 ceramic and the antenna size is 23.3 mm x $\times $ 13 mm x $\times $ 0.5 mm. The measurement results indicate that the antenna achieves an impedance bandwidth of 13.59% below -10dB, with an average gain of approximately 7 dBi and a peak gain of 7.4 dBi in 28.1-32.2 GHz. Therefore, the 1*2 antenna proposed in this paper has the advantages of compact and planar structure, easy fabrication, and easy integration into RF circuits, which is very suitable for Ka-Band applications.