Small form factor dual band (28/38 GHz) PIFA antenna for 5G applications

This paper presents for the first time, the design of a dual band PIFA antenna for 5G applications on a low-cost substrate with smallest form factor and widest bandwidth in both bands (28 GHz and 38 GHz). The proposed dual band PIFA antenna consists of a shorted patch and a modified U-shaped slot in the patch. The antenna shows good matching at and around both center frequencies. The antenna shows clean radiation pattern and bandwidth of 3.34 GHz and 1.395 GHz and gain of 3.75 dBi and 5.06 dBi at 28 and 38 GHz respectively. This antenna has ultra-small form factor of 1.3 mm × 1.2 mm. Patch is shorted at one end with a metallic cylindrical via. A CPW line and a feeding via are used on the bottom side of the substrate to excite the PIFA antenna patterned on the top side of the substrate which also facilitate the measurements of the antenna at mm-wave frequencies. The antenna was designed on low cost Isola FR406 substrate.