A tunable antenna comprising: • a circuit board, wherein the circuit board comprises a top surface, a bottom surface, and a side surface, wherein the top surface and the bottom surface are connected by the side surface, • an antenna body configured to transmit and receive a signal of a first frequency band and comprising a feed end (na) and a ground pin (lib), • an electrical tuning network comprising: ∘ in a first alternative, a ground point connected to the ground pin of the antenna body by only using the electrical tuning network, and the electrical tuning network only comprises an inductor, a first tunable capacitor (12b-1) with a tunable capacitance value and a second tunable capacitor (12b-2), wherein the inductor is connected in series to the first tunable capacitor (12b-1), and the second tunable capacitor (12b-2) is connected in parallel to the inductor and the first tunable capacitor (12b-1), ∘ in a second alternative instead of the first alternative, the ground point is connected to the ground pin of the antenna body by only using the electrical tuning network, and the electrical tuning network only comprises the inductor and the first tunable capacitor with the tunable capacitance value, wherein the inductor is connected in series to the first tunable capacitor, • a parasitic antenna stub configured to excite a high-frequency mode of the first frequency band, • a third tunable capacitor disposed at an end of the parasitic antenna stub, • wherein in a direction starting from a first point on the side surface to a second point on the side surface, a sequence of the feed end, the ground point and the third tunable capacitor is disposed on the side surface. • a circuit board, wherein the circuit board comprises a top surface, a bottom surface, and a side surface, wherein the top surface and the bottom surface are connected by the side surface, • an antenna body configured to transmit and receive a signal of a first frequency band and comprising a feed end (na) and a ground pin (lib), • an electrical tuning network comprising: ∘ in a first alternative, a ground point connected to the ground pin of the antenna body by only using the electrical tuning network, and the electrical tuning network only comprises an inductor, a first tunable capacitor (12b-1) with a tunable capacitance value and a second tunable capacitor (12b-2), wherein the inductor is connected in series to the first tunable capacitor (12b-1), and the second tunable capacitor (12b-2) is connected in parallel to the inductor and the first tunable capacitor (12b-1), ∘ in a second alternative instead of the first alternative, the ground point is connected to the ground pin of the antenna body by only using the electrical tuning network, and the electrical tuning network only comprises the inductor and the first tunable capacitor with the tunable capacitance value, wherein the inductor is connected in series to the first tunable capacitor, ∘ in a first alternative, a ground point connected to the ground pin of the antenna body by only using the electrical tuning network, and the electrical tuning network only comprises an inductor, a first tunable capacitor (12b-1) with a tunable capacitance value and a second tunable capacitor (12b-2), wherein the inductor is connected in series to the first tunable capacitor (12b-1), and the second tunable capacitor (12b-2) is connected in parallel to the inductor and the first tunable capacitor (12b-1), ∘ in a second alternative instead of the first alternative, the ground point is connected to the ground pin of the antenna body by only using the electrical tuning network, and the electrical tuning network only comprises the inductor and the first tunable capacitor with the tunable capacitance value, wherein the inductor is connected in series to the first tunable capacitor, • a parasitic antenna stub configured to excite a high-frequency mode of the first frequency band, • a third tunable capacitor disposed at an end of the parasitic antenna stub, • wherein in a direction starting from a first point on the side surface to a second point on the side surface, a sequence of the feed end, the ground point and the third tunable capacitor is disposed on the side surface.