This paper presents a novel design of a compact, wideband tunable microstrip filtenna system for effective spectrum sensing in cognitive radio (CR) applications. The proposed filtenna structure has a total bandwidth of 1.63,text{GHz} and flexible frequency scanning design throughout the frequency range from 1.93,text{ to },3.56,text{ GHz} with high selectivity and narrow bandwidths ranging from 39.9,text{to}53,text{MHz}. Frequency tuning is accomplished electrically via integrating a varactor diode into the filtenna construction. The filtenna is realized on a Rogers TMM4 substrate with h=1.52,text{mm} thickness and relative dielectric constant of {varepsilon }_{r}=4.5 with dimensions of (25times 35), {text{mm}}^{2}. The obtained gain and efficiency of the filtenna ranged from 0.7 to 2.26,text{dBi} and 49% to 60%, respectively, within the tuning range. Simple biasing circuitry, wideband operation, and compact planar structure are distinctive and appealing aspects of the design. For the manufactured prototypes, a significant level of agreement is found between the simulated and measured results in terms of scattering parameter {text{S}}_{11} and radiation patterns at different operating frequencies.