A device having a variable inductor includes an inductor having an inductance, a first conductor having a first grounding property, and a second conductor having a second grounding property. The device further includes a first single-mesh structure including a first grid. The first grid includes a first conducting wire electrically connected to the first conductor, and a second conducting wire electrically connected to the first conducting wire and the first conductor, wherein the first conducting wire, the second conducting wire and the first conductor are configured to form a first loop corresponding to the inductor for tuning the inductance. The first single-mesh structure further includes a second grid. The second grid includes a third conducting wire electrically connected to the first conducting wire and the second conductor, and a fourth conducting wire electrically connected to the third conducting wire and the second conductor, wherein the third conducting wire, the fourth conducting wire and the second conductor are configured to form a second loop corresponding to the inductor for tuning the inductance.