A multiband reconfigurable slot antenna for wireless applications

This research presents a novel four band frequency reconfigurable antenna for 1.6 (Global Navigation Satellite system (GNSS)), 2.5 (Lower Worldwide Interoperability for Microwave Access (WiMAX)), 5.8 (Wireless local area network (WLAN)) and 9.8 GHz (X-band) frequency bands. The antenna has a compact size of 0.18λ₀×0.18λ₀×0.0096λ₀ at lower resonance of 1.8 GHz and is printed on FR4 material with height (h) = 1.6 mm, dielectric constant ((ε_r)=4.4 and loss tangent (δ) = 0.02. Multiband phenomenon in the antenna is achieved by etching trapezoidal slot in the radiating monopole and rectangular slots in the ground plane. Frequency reconfiguration in the proposed structure is achieved by placing PIN diode switch between rectangular slot placed in the ground plane. During OFF state, the antenna exhibit quad band with S₁₁ < −10 dB bandwidth of about 11.1% (1.7–1.9 GHz), 10.52% (2.7–3.0 GHz), 5.52% (5.6–5.9 GHz) and 9.3% (9.2–10.1 GHz) under simulation and of about 6.06% (1.6–1.7 GHz), 11.76% (2.4–2.7 GHz), 3.44% (5.7–5.9 GHz) and 6.25% (9.3–9.9 GHz) in measurement respectively. During ON state of PIN diode, the antenna operates at dual bands (5.8 and 9.5 GHz) with S₁₁ < −10 dB bandwidth of about 3.44% (5.7–5.9 GHz) and 7.65% (8.8–9.5 GHz) under simulation and of about 8.54% (5.6–6.1 GHz) and 3.17% (9.3–9.6 GHz) in measurement respectively. The antenna exhibits good impedance matching, radiation characteristics and gain across their operational bandwidths.