Frequency Tunable Slot Antenna for Wireless Applications

An inset-fed slot based rectangular microstrip reconfigurable antenna designed on a
$31.5\times 27\ \text{mm}^{2}$
Rogers RT 5880 substrate with relative permittivity
$\epsilon\mathrm{r}=2.2$
, 0.79 mm thickness and loss tangent = 0.0009 is proposed in this work. A U-shaped slot is incorporated in the patch to improve impedance matching performance. A PIN diode is added to the slot to achieve reconfigurability between single and dual bands. A single band with center frequency 5.3 GHz, 1.67 % impedance bandwidth and 6.3 dBi gain is obtained in mode 1 (diode is in OFF state). In mode 2 (diode is in ON condition), a dual band is achieved at frequencies 4.48 and 5.38 GHz with 0.57% and 1.12% impedance bandwidths and 4.8 dBi and 6.3 dBi gains respectively. The antenna performance is analyzed in terms of better impedance matching, high gain and directional far field radiation characteristics. The suggested layout is suitable to be used for WiMAX (Worldwide Interoperability for Microwave Access) and aeronautical radionavigation applications.