Gain Enhancement in UWB Antenna using AMC Reflector for Wireless Applications

Here a 3×3 array of dual band AMC metamaterial surface having size of 15 mm ×15 mm is proposed to increase gain value of a UWB antenna with dimension of 30 mm × 30 mm. Every notch created on AMC cell contributes in the generation of two resonance frequencies at 4.7 and 9.9 GHz. The structure of unit cell contains square shaped patch, a ring structure along with a central plus shape slit. AMC feature of having 0-degree reflection phase at two resonance frequencies (4.7 and 9.9 GHz) is also noticed here. Proposed AMC cell is utilized as reflector plain to increase gain and radiation features. Both designs (unit cell and wideband antenna) utilized FR-4 substrate having thickness 1.6 mm and dielectric constant of 4.4. Initially wideband antenna has 5.7 dB of gain and later it was increased to 8.3 dB by using AMC. The effect on metamaterial antenna gain with varying air gap (d) and array size is studied along with the impact on antenna parameters (gain, directivity and radiation pattern) due to grounded or ungrounded AMC structure is also studied to get optimum outcomes. Computer simulation technology (CST) software is used for simulation and simulation outcomes are confirmed with experimental outcomes and they show acceptable agreement.