A Truncated Waveguide Fed by a Microstrip as a Multi-Band WLAN Antenna

This paper presents a small truncated waveguide fed by a microstrip line through a transverse coupling slot for multi-band WLAN applications. The analysis of the presented antenna has been performed by replacing the feeding microstrip line with its equivalent Magnetic-Wall Waveguide (MWW) model and using an in-house Method of Moments (MoM) to analyze the structure. The use of entire-domain basis functions both on the slot and on the truncated waveguide apertures allows to obtain a very efficient analysis by exploiting the waveguide modes orthogonality. The proposed radiating element allows to obtain a high radiated power, with a very low cross-polar component in the radiated field, with a -10 dB bandwidth that covers the required frequencies for multi-band WLAN applications (5.2/5.4/5.8 GHz).