This letter presents a novel differential filtenna for microwave systems at 2.4 GHz on planar technology. This filtenna exhibits 5% bandwidth with a 3-pole Chebyshev response. The filtenna uses a square patch as radiating element combined with λ/2 resonators. Experimental and simulated results are presented with good agreement. Moreover, the experimental common and differential mode radiation patterns are presented showing an attenuation greater than 15 dB for the common mode.