The design and simulation of feederlines of log-periodic dipole antenna in microwave band

This paper studied the impact of different distance and angles of feedlines to the log-periodic dipole antenna (LPDA). The study found that in the parallel manner (angle is 0) and different distance between feederlines(d is modified from 2mm to 14mm), VSWR is larger than 3. So the optimization is proposed that the feederlines are inclined by 5° to get wider work band (from 0.47GHz to 3.8GHz) with 8dB gain as well as low VSWR. Thanks to this modification, the LPDA can provide superior performance in the measurement of multiple polarization directions and omni-direction pattern above 2GHz.