A Broadband Microstrip-Fed Patch Antenna With Harmonic Suppression

This paper presents a single-layer microstrip patch antenna with improved bandwidth and harmonic suppression. A λ/4 resonator is introduced and coupled in proximity to the feeding line for bandwidth enhancement and a spur-line is applied for high order harmonic suppression. Compared with other dual-resonance patch antennas, the proposed antenna has attractive low-profile property and simple structure. The structure, working principle, and measured results are extensively described. The operating bandwidth is from 3.42 GHz to 3.6 GHz (5.13%) with a reflection coefficient less than-10 dB, while harmonic suppression over wide frequency range from 3.6 to 8.5 GHz is achieved.