Characterization of 4×4 high gain microstrip array antenna for 3.3GHz WiMAX application

This paper presents the design of microstrip array antenna for 3.3GHz WiMAX (Worldwide Interoperability Mobile Access) application. The proposed antenna comprises of 16 rectangular patches with microstrip line feeding network established using a quarter-wavelength transformer impedance matching technique. To avoid grating lobes affected by the spacing between patches, the patch separation to the adjacent patches is set to be 0.6 of wavelength. Hence, in order to achieve high gain required by the WiMAX specifications, the array consisted of 16 patches is applied where the patches are structured in 4×4 (columns x rows) formation. The antenna structure is then deployed on an Arlon DiClad 527 substrate which the thickness, dielectric constant and loss tangent are 1.6mm, 2.5 and 0.0022, respectively. The characterization result of return loss, VSWR (Voltage Standing Wave Ratio), radiation pattern, and gain are presented consecutively. From the result, it shows that the proposed antenna has the overall gain of 16.02dB and the return loss of 29.85dB that corresponds to VSWR of 1.07 at center frequency of 3.35GHz, whilst the working bandwidth is 150MHz ranges from 3.25-3.40GHz.