Antenna having connecting circuit

An antenna having a connecting circuit, comprising:

• a substrate, having a first surface;
• a grounding metal strip;
• a first radiating metal strip, located on the first surface of the substrate, wherein the first radiating metal strip is not connected to the grounding metal strip;
• a second radiating metal strip, located on the first surface of the substrate, wherein the second radiating metal strip is not connected to the first radiating metal strip, and the first radiating metal strip is located between the second radiating metal strip and the grounding metal strip;
• and
• a connecting circuit, located on the first surface of the substrate, and used for electrically connecting different positions on the grounding metal strip and on the second radiating metal strip, so as to form a plurality of resonant paths of different lengths between the grounding metal strip and the second radiating metal strip, wherein
• the first radiating metal strip radiates at least one first resonant mode, and the second radiating metal strip is coupled to the first radiating metal strip to produce at least one second resonant mode;
• the resonant paths are switched via the connecting circuit, so that the frequency of the second resonant mode varies between different values.