Multi-Band Antenna Design by Reshaping Surface Currents of Higher Order Mode Using CMA Method

A multi-band antenna design by surface current reshaping of higher-order modes is presented. This method utilizes characteristic mode analysis to modify the conventional circular patch antenna in accordance with the surface current distribution of higher-order modes at the L5, S, and L1 bands using CMA. The antenna is evaluated up to four modes inducing fundamental mode. The S and L1 bands are obtained by exciting reshaped higher-order modes, while the L5 lower band is obtained by exciting the fundamental mode using full-wave analysis with 50 ohm coaxial feed. The measurement results are very similar to simulated antenna results. The measured operating frequencies of the proposed antenna are 1177.00 MHz (L5-band), 1575.00 (L1-band) MHz, and 2497.50 (S-band) MHz with associated impedance bandwidth (S11 <= -10 dB) are 25.30 MHz (1164.40-1189.70 MHz), 65.30 MHz (1535.50-1600.80 MHz), and 48.60 MHz (2464.10-2512.70 MHz) having desired gain with hemispherical radiation characteristics. These bands are used in Global Positioning Services (GPS) and in Indian Regional Navigation Satellite System (IRNSS) applications.