Maximizing the Radiated Power of Patch Antenna using Characteristic Modes

A characteristic mode analysis (CMA) based optimization method is presented to maximize a rectangular patch's radiated power. The conventional narrowband microstrip antenna was designed on an FR-4 substrate resonating at 2.86 GHz, but its radiated power was maximum at 2.96 GHz. The single characteristic mode participated in antenna's characterization, which showed resonance at 2.96 GHz. Characteristic modes were controlled to shift the frequency of the radiated power where matching occurs or return loss is minimal. It is demonstrated that reactive loading influences the modal resonance of the antenna. Reactive loading using slits tends to optimize the antenna's modal significance and modal weighting coefficient (MWC). The optimization of MWC acted as an indicator to maximize the radiated power of the antenna.