A novel ±45° dual-polarized microstrip patch antenna based on “L”-shaped probe feeding is designed and simulated for optimization. Two orthogonal “L”-shaped probes with a height difference are used for mutual coupling feeding to achieve dual polarization, significantly increasing the antenna's channel capacity. The copper metal columns between the two dielectric substrates play the role of feeding and radiation. The microstrip radiation patches are connected through metalized vias, and symmetrical “τ”-shaped grooves designed with openings facing inward are adopted to increase the resonance frequency point, the polarization patch is designed in an “S”-shape to expand the bandwidth. Simulation results show that the S11 of the antenna is less than -10 dB within the frequency bands of 2.08～2.77 GHz & 3.66～5.36 GHz, the relative impedance bandwidth is 66.15%, the gain is not less than 6 dBi, the radiation efficiency is above 90%, the isolation between ports is greater than 10 dB, and the cross-polarization level is greater than 20 dB. Physical fabrication and actual measurements demonstrate good agreement between the measured and simulated results at port 1, while minor deviations at port 2 are attributed to fabrication and testing conditions but remain within acceptable limits. Compared with similar studies, the proposed antenna features wide bandwidth, compact structure, and ease of fabrication, making it suitable for C-band（3700～4200 MHz）and WLAN（2400～2484 MHz and 5150～5350 MHz）wireless transceiver communication systems.