Heptaband Inverted-F Antenna With Independent Resonance Control for Mobile Handset Applications

In this letter, a compact inverted-F antenna (IFA) with independent resonance control is presented. The proposed antenna covers the heptaband (GSM850/900/DCS/PCS/UMTS/LTE2300/2500) for mobile handset applications. The proposed structure consists of four radiating branches. Each branch operates at a quarter-wavelength mode as the fundamental resonant mode, and the proposed antenna has quintuple resonant frequency (f₁, f₂, f₃, f₄, and f₅) characteristics. One remarkable feature of the proposed antenna is that each of the four resonant frequencies can be controlled independently without affecting the other four resonant frequencies (f₅: harmonic of the fundamental frequency f₁).