Abstract: A wideband patch antenna under multi-mode resonance is designedinthis paper.By etching two slots on a rectangular patch, the antenna workssimultaneously in two orthogonal modes of TM10 and anti-phased TM30, which broaden the bandwidth of the antenna. In addition, four square slits are etched at corners of the radiation patch, improving the impedance matching of the antenna at low frequencies, effectively excite the slot mode, which further broadens the operating bandwidth of the antenna.The antenna introduced a aperture-coupled feeding method to excite three working modes at the same time.In order to improve the impedance matching of the antenna, a square patch is loaded on the terminal of the microstrip feeding line.Measured and simulated results are foundin good agreement with each other and both of them showthat impedance bandwidth is 27.9%. Besides, thegood broadside radiation is achieved. The peak gain of the antenna is 6.3 dBi.