Compact Wideband Yagi Loop Antenna Array for 5G Millimeter-Wave Applications

A compact wideband Yagi loop antenna array for 5G Millimeter-Wave (mm-wave) applications is proposed in this paper. The antenna element employs a transition from grounded coplanar waveguide (GCPW) to the parallel line, which acts as the feeding line for convenient integration. The loop is formed by a combination of two vias and two strips printed on the top and bottom layers of the substrate, which shows a very compact structure. The driver and director of the Yagi antenna adopt the form of loop, which effectively reduces the overall transverse dimension of the antenna element to 4 mm (0.34 X at the lowest working frequency). Simulated results for the antenna element show an impedance bandwidth of 24.4% from 25.54 to 32.65 GHz and a peak gain of 8.25 dBi at 29.5 GHz. In order to enhance the antenna gain and verify the feasibility of the antenna element, a planar 1x4 antenna array is designed, fabricated and measured. The measured results for the array demonstrate an impedance bandwidth of 23.77% from 24.53 to 31.15 GHz and a peak gain of 13.45 dBi. The proposed antenna features a compact size, low fabrication cost, wide bandwidth and good radiation performance, which is well suited for 5G mm-wave applications on handsets.