Frequency Reconfigurable Multiband Planar Antenna for Multistandard Communications

In this work, a novel frequency-reconfigurable printed antenna is proposed. The structure consists of a capacitively loaded loop (CLL) introduced into the near field region of a coplanar waveguide (CPW) printed monopole antenna. By embedding a pair of capacitors C1 and C2 between each CLL element and the ground plane, we can easily generate and control two resonant frequencies in addition to the main resonant frequency of the reference structure at 2.45GHz. The proposed antenna achieves a frequency reconfigurable band with tuning range from 0.6GHz to 1.06GHz (LTE 600, LTE 700 and GSM 900 bands) when varying the C1 capacitance values from 1 to 7pF and 1.35 to 2.03 GHz (AWS, DCS and UMTS bands) when varying the C2 capacitance values from 0.1 to 0.7pF with reasonably good gain (>1.5 dBi) and efficiency (82%). The presented antenna has a compact size of $50 \times 35$ mm2. The proposed design is validated by simulations, displaying good results of impedance mismatch, gain pattern and radiation efficiency. The reconfigurability, range tuning and compact size makes the presented antenna well suitable for the future 5G systems to achieve dynamic spectrum access and deal with the spectrum shortage problem.