Design of Frequency-Reconfigurable Triband Dipole Antenna Using Capacitive Loading

In this work, a novel frequency-reconfigurable printed dipole antenna is reported. By embedding a capacitor in the capacitively loaded loop (CLL), we can easily generate and control an additional resonant frequency F3 besides the main resonant frequency of the basic dipole antenna F
₁
= 2.3GHz (LTE band) and the CLL element F2 = 1.51GHz (GPS band). The proposed antenna achieves a frequency reconfigurable band with tuning range from 1.7 to 2.03 GHz (AWS, DCS and UMTS bands) when varying the capacitance values from 2 to 8pF with good gain and efficiency. The presented antenna has a compact size of 40 × 70 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.