A wideband substrate integrated waveguide (SIW) antenna using shorted vias for 5G communications

Abstract

Antennas that have a higher gain and greater efficiency across a broader frequency range are more advantageous and effective. Achieving these characteristics at higher frequency ranges while maintaining a small footprint adds complexity to antenna design. This study investigates and designs a slotted patch antenna (SPA) for the 5G n257 (28 GHz) and n258 (26 GHz) frequency bands, which are supported by a substrate-integrated waveguide (SIW) cavity. This antenna features excellent gain and efficiency coupled with a broader bandwidth. The developed antenna has a wide frequency bandwidth of 3.9 GHz, approximately 14.4% of the central frequency and a peak gain of 7.5 dB. Slots having L type shape are etched into the ground plane, and two shorting vias are placed below each L slot to improve the impedance bandwidth. The dielectric substrate material RT/Duroid 5880 with εr = 2.2 and a thickness of 0.787 mm are employed. The discussed antenna operates between 25.1 GHz and 29 GHz. The antenna is excited by a 50 Ω microstrip transmission line to SIW transition modified taper for optimal electrical performance. The developed antenna displays dual resonant characteristics, one at 26.1 GHz and another at 28.5 GHz. The overall physical dimension of the antenna is only 14 × 18 × 0.787 mm3. The electrical dimensions are 1.26 λu × 1.62 λu × 0.0708 λu, where λu is the wavelength at the centre frequency in a vacuum. The antenna's performance can be comprehended using the reflection coefficient (S11), radiation patterns and electric field distribution. The research described herein compares the simulated antenna's performance and analysis with the experimental prototype. The suggested antenna has high gain, small size and broad spectral coverage—all of which make it ideal for 5G applications.