A compact planar ultra-wideband handset antenna with L-shaped extended ground stubs

In this letter, a compact planar ultra-wideband mobile antenna with L-shaped extended ground stubs is presented. The proposed handset antenna consists of two planar meandered monopole radiating elements, i.e., main antenna and auxiliary antenna respectively, located at the diagonal corners of mobile phone printed circuit broad with standard size of 136 x 68 mm(2). Each radiating element is composed of two arms and a L-shaped extended ground stub, jointly achieving multiple resonances and ultra-wideband impedance matching with a compact size. The effect of the L-shaped ground stub is investigated in detail. The proposed antenna has a compact size of 31.4 x 12 mm(2), printed simple structure and full-band coverage (GSM850 and 1.6-5.4 GHz) for wireless handsets systems, including GSM850, DCS1800, PCS1900, UMTS, LTE, WiMAX, and WLAN in 4G and 5G communication systems. The optimized antenna prototype is fabricated and measured. The measured results show that the reflection coefficients are less than -6 dB over the operating bands and the mutual coupling between two ports is less than -20 dB. Good agreement is obtained between the simulated and measured results. The results demonstrate that the proposed handset antenna has good characteristics of ultra-wideband, isolation, gain, and radiation pattern, and is a good candidate as a terminal antenna for handsets applications.