Design of a Wide-Band Blade Monopole Antenna in 135-175 MHZ Band

Abstract

This paper presents the design of a wideband blade shaped monopole antenna with a horizontally mounted aluminium tube on top of the blade covering 135-175 MHz frequency band using Electromagnetic Simulation software (CST Microwave Studio TM) along with a matching network whose characteristics have been evaluated by the Optimal Matching Network Identifier (OMNI) algorithm. OMNI algorithm is a search technique used in computing, to find the optimum solution. The conventional quarter wavelength monopole antenna is a narrow band antenna with bandwidth of the order of 5% to 10% at its centre frequency. In order to increase the bandwidth of the antenna, a proper matching network has been incorporated along with it. Toroidal inductor based matching networks have been designed, and their characteristics are evaluated using Optimal Matching Network Identifier (OMNI) program in MATLAB software. By consolidating MATLAB and CST simulated results, the antenna prototype along with the optimal matching network has been practically implemented, and corresponding results have been verified. The details of simulated and measured results are also included. The proposed antenna finds numerous applications in various wideband communication systems.