High-gain high-selectivity TE20-mode SIW-fed metasurface filtenna array for 5G millimeter-wave applications

A high-gain high-selectivity 4 x 4 metasurface (MS) filtenna array is presented in this paper for 5G millimeter-wave (mmW) applications. The TE20-mode substrate integrated waveguide (SIW) with two parallel coupling slots is applied as the differential feeding structure, which can produce a wide impedance bandwidth and good radiation performances, simultaneously. Additionally, the TE20-mode SIW feeding line is well designed to operate as a lambda/2 short-circuited line at the upper edge frequency to gain a radiation null. Meanwhile, a folded U-shaped slot is etched on each MS unit to generate a radiation null at the lower edge. As a result, a passband which covers our 5G mmW band (24.25-29.5 GHz) of interest can be realized. To validate the design, a 4 x 4 MS filtenna array was manufactured and measured. The simulated and measured results are in good agreement, demonstrating a -10 dB impedance bandwidth of 19.8%, a flat gain variation with a maximum value of 19.82 dBi, symmetrical radiation patterns, low cross-polarization levels of -30 dB, and high out -of -band rejection levels of 25 dB.