Design and optimization of a non-cross feed printed log periodic dipole array antenna using particle swarm optimization

This paper presents an optimized design of non-cross feed Printed Log Periodic Dipole Array (PLPDA) antenna using Particle Swarm Optimization (PSO) technique. An improved feed structure of non-cross fed dipoles is chosen as reference antenna, which avoids the complexity of conventional feeding with long coaxial line and CPW feed. A simple fitness function based on S11 parameter is used in PSO to achieve the goal of size reduction and bandwidth enhancement. Simulation results on CST software are verified by a manufactured prototype of proposed PSO optimized non-cross feed PLPDA antenna using FR 4 substrate with a thickness of 1.6 mm. The measured bandwidth of proposed antenna is 4.2-11.6 GHz with a fractional bandwidth of 93.6%, whereas the reference antenna covers the frequency range from 4.2 to 9.2 GHz with a fractional bandwidth of 74.6%. The effective area of the proposed design is 30% lesser than reference antenna. Proposed antenna is offering peak gain of 7.6 dBi with an average gain of 5.5 dBi in desired band. The electrical size of optimized structure is 0.53λ at center frequency. Thus, proposed antenna is offering higher bandwidth and significantly smaller size with less complexity and lower cost, while maintaining the log periodic nature and gain.