Log periodic antennas are widely used in ultra wideband applications. This paper compares the coplanar waveguide and microstrip feed of log periodic array antennas in terms of gain, bandwidth, design complexity and also the effect of the antenna on different substrates. The design criteria of both types of antennas are discussed in detail. The two different types of feeding techniques for the antenna are simulated using High Frequency Structure Simulator which uses efficient Finite Element Method for rigorous electromagnetic analysis. The results are compared and comparison table gives the clear idea of choosing the feed and also the substrate material. © 2015 IEEE.