Compact monopole with a band‐stop matching circuit for LTE/WWAN smartphone

Abstract

An LTE/WWAN monopole antenna with a compact size of 12.5 × 28.7 mm2 for smartphone applications is designed. The antenna is formed by an L‐shape driven branch, a parasitic shorting branch, and a band‐stop matching circuit. By capacitive coupling and loading a matching circuit, the antenna generates four resonant modes in the working bands. The band‐stop matching circuit is applied to enlarge the bandwidth of the low working band. The measured −6 dB impedance bandwidth of the presented antenna ranges from 683 MHz to 962 MHz and from 1632 MHz to 2710 MHz, covering LTE/WWAN eight‐band operation. Acceptable radiation performances are achieved over the working bands. The measured efficiencies are 45.4%‐61.2% and 44.5%‐66.4% and the measured gains are −0.6 dBi‐2.0 dBi and 0.07 dBi‐2.69 dBi in the low and high working band, respectively.