A Miniaturized Multi-Wideband Antenna for Variable-Size Tablet Computers and Mobile Phones

This paper discusses a miniaturized multi-wideband tablet antenna having a compact size of 20 × 9.6 × 1.8 mm³. The antenna is modeled on FR-4 substrate with thickness of 0.8 mm. The antenna covers LTE 700/2300/2500/3500, GPS 1575.42 MHz, GSM 850/1800/1900, UMTS 2100, Bluetooth 2.4 GHz and 5.2/5.8 GHz WLAN bands. The wideband operation is achieved by a novel inverted-F type structure which is capacitively coupled with two λ/4 microstrip resonators. Impedance matching at lower bands is further improved by a high-pass matching circuit integrated with the antenna feed. The proposed antenna has reasonable gain over all covered bands, low specific absorption rate (SAR) and high radiation efficiency from 80-90% over all LTE and WLAN bands.