A Millimeter-Wave CP Filtering Magnetoelectric Dipole Antenna With SIGW Technology

Abstract

In this letter, a circularly polarized (CP) filtering magneto-electric (ME) dipole antenna based on substrate-integrated gap waveguide (SIGW) technology is proposed for millimeter-wave applications. The antenna element primarily consists of four square patches, four metallic vias, and a fork-shaped SIGW feeding network. By appropriately chamfering the square patches, a minimum axial-ratio point can be introduced to broaden the axial-ratio bandwidth (ARBW). It should be noted that the radiating element, coupling slot, and feeding network can be equivalently represented as a third-order filter, resulting in high upper stopband suppression. To further enhance the lower stopband filtering performance, four square strips and two U-shaped strips are incorporated. For validation, a 1 × 2 CP filtering ME dipole antenna array is designed and fabricated. Measurement results show a −10 dB impedance bandwidth of 12.6%, a 3 dB ARBW of 11.6%, a peak gain of 9.16 dBi, and out-of-band suppression exceeding 19.3 dB.