A compact microstrip patch antenna with bandwidth enhancement

In this paper, a compact microstrip patch antenna with bandwidth enhancement and harmonic suppression has been presented. The radiating patch is coupled and excited by a microstrip stub which is a non-radiating quarter wavelength resonator. Because the coupling quarter wavelength resonator operates at another resonant frequency close to center frequency of the radiating patch, the bandwidth is enhanced effectively. The proposed antenna acquires 6.1% bandwidth (from 4.73 to 5.03GHz), with a satisfactory radiation performance within the bandwidth and the harmful higher order radiating modes have been obviously suppressed. Moreover, the single quarter wavelength resonator makes it more flexible to excite patch and easier to be arranged in arrays for its compact and simple structure.