Design and Simulation of a Quarter Wavelength Gap Coupled Microstrip Patch Antenna

The bandwidth obtained from a conventional rectangular microstrip patch antenna is not sufficient for many purposes. The bandwidth of a rectangular microstrip patch antenna can be improved by gap coupling parasitic patches to it, along its radiating and or non radiating edges. However, the resulting antenna structure has larger patch area and overall size than the unmodified conventional rectangular microstrip patch antenna. The microstrip patch antenna design presented here employs gap coupling technique to improve its bandwidth and reducing patch size by 50 %. The half wave length long patch, of the conventional rectangular microstrip patch antenna, is divided along its width, into two half parts which are quarter wave length long, for two different TM10 mode frequencies. These quarter wave length long patches are then gap coupled along their non radiating edges. One of these patches is probe fed. The simulation of the proposed design predicts nearly two fold bandwidth enhancement over the conventional half wavelength long microstrip patch antenna.