Printed Ridge Gap Waveguide Fed Filtering Magnetoelectric Dipole Antenna Array for 5G Millimeter-Wave Applications

In this communication, a wideband filtering magnetoelectric (ME) dipole antenna without any extra filtering circuits is first proposed for millimeter-wave (MMW) applications. To improve the radiation efficiency, the printed ridge gap waveguide (PRGW) feeding network is employed. The proposed antenna mainly includes four parts: radiation patches, driven stubs, a square substrate integrated waveguide (SIW) cavity, and a fork-shaped PRGW feeding structure. By introducing four U-shaped defected ground structures (DGSs), a radiation null can be obtained at the upper stopband. Meanwhile, two rectangular strips are added to the radiation patches, which not only widens the impedance bandwidth but also enhances the lower stopband suppression level. In addition, the roll-off rate near the lower and upper band edges can be further improved by adding four folded strips. Consequently, desired filtering characteristics are realized. For verifying, a 2 x 2 filtering ME dipole antenna array is fabricated and tested. Measurement results indicate that an impedance bandwidth (|S-11| < -10 dB) of 23.7% can be achieved, which completely covers the 5G MMW band (24.25-29.5 GHz). Besides, an average gain is about 14.5 dBi within the frequency band of interest, whereas the level of the out-of-band radiation suppression is greater than 19.5 dB. What is more, a radiation efficiency of 95.9% is observed at 27.5 GHz.