High Gain and Wide Bandwidth Array Antenna for Sector Beam Pattern Synthesis

This paper presents a novel design structure of a series fed array antenna for desired shaped beam pattern synthesis. The desired beam shape is obtained by varying the width of patch elements. A uniform array is designed for the desired frequency, and then the proportionate values of the widths are calculated using amplitude coefficients obtained from the Woodward Lawson array synthesis method, while keeping excitation phase and inter element spacing constant. The proposed antenna is designed and simulated in HFSS. A prototype is fabricated on FR-4 epoxy dielectric material and tested at 12.5 GHz. The overall antenna has a compact size of 112 mmx34 mmx0.8 mm. The array structure exhibits impedance bandwidth of 1.8 GHz and fractional bandwidth of 15.2%, from 11 GHz to 12.8 GHz frequency range with return loss of -29.6 dB and high gain of 14.7 dB. The series fed configuration results in a VSWR of 1.38 and considerably low side lobe level of -21 dB. There is a fine similarity between simulation and fabrication measurement parameter values such as return loss, VSWR, gain, and bandwidth.