Substrate integrated waveguide omnidirectional filtering antenna with a controllable radiation null for 5.8 <scp>GHz WiFi</scp> application

A filtering antenna composed of a monopole and two stacked circular substrates integrated waveguide (SIW) cavity for 5.8 GHz WiFi application is proposed in this letter. Cross-coupling between the feeding probe second SIW resonator utilized to generate radiation null at frequency above working band. By properly designing location size coupling slot resonators, can be adjusted. Experimental results fabricated show good agreement with simulated performance. The measured response has return loss greater than 10 dB fractional bandwidth 16.4% centered 5.48 while there 6.85 GHz. Omnidirectional patterns are achieved horizontal plane maximum gain 1.1 dBi. merits compact stopband suppression.