Compact frequency-tunable antenna with a GaAs switch for mobile handset

A novel compact tunable antenna for a mobile handset is proposed. The antenna occupies small 50 × 10 × 2 mm volume and covers 800 MHz, 1.7-2 GHz, and 1.5 GHz bands. The antenna is composed of a monopole element for 800 MHz and a skeleton antenna for 1.5 GHz and 1.7-2.1 GHz that cuts the inside of the planar antenna. Proposed antenna size is the same as a conventional antenna designed for 800MHz and 1.72.1GHz operation despite of the additional 1.5 GHz frequency band. The proposed antenna has achieved -6dB return loss at 800 MHz, 1.5 GHz, and 1.7-2.1 GHz bands. The total efficiency at the middle band is less than -3dB. We have clarified the mechanism of the decreased efficiency at the 1.5 GHz band and realized an efficiency improvement by utilizing a reflection-type RF switch instead of an absorption-type switch.