Small-size printed coupled-fed antenna for eight-band LTE/GSM/UMTS wireless wide area network operation in an internal mobile handset

A simple small-size printed antenna for eight-band long-term evolution (LTE)/GSM/UMTS wireless wide area network operation in an internal mobile handset application is proposed. Occupying a compact size of 15 × 40 mm² on the ungrounded region of the system circuit board and a low profile of 4 mm, the presented antenna is a coupled-fed configuration. With the longer branch of the feeding strip, a λ/4 resonant mode at around 2.7 GHz can be obtained to cover the desired LTE2500 operation. A fundamental λ/4 resonant mode over the desired lower band of LTE700/GSM850/900 can also be generated at 750 MHz by the long meandered coupling strip (length of about 113 mm). Moreover, two additional higher-order resonant modes at around 1.75 and 2.25 GHz can also be obtained by the coupling strip. By including a chip inductor L at the feeding point, the impedance matching over the lower and upper bands can be improved in order to achieve the two wide operating bands of 698-960 and 1710-2690 MHz. With the following properties of small size, ease of fabrication and good radiation characteristics, the proposed antenna is a good candidate for the fourth LTE mobile phone applications.