Low-profile Broadband High-Isolation Microstrip Dual Antenna Pair

This paper presents a low-profile, multi-mode, broadband, high-isolation microstrip dual antenna pair, which consists of two central symmetry antenna elements. Each individual antenna element consists of a rectangular radiation patch, a metal column, a lumped capacitor, and a feed port. The antenna could excite multi-mode resonance by adding the metal columns and the capacitor elements to a traditional microstrip patch antenna, achieving low-profile broadband characteristics while providing support to the radiation patch and increasing mechanical stability. The proposed antenna has a volume of 89.7 $\mathrm{mm} \times 24.5 \mathrm{~mm} \times 0.5 \mathrm{~mm}\left(1.345 \lambda_{0} \times 0.368 \lambda_{0} \times 0.009 \lambda_{0}\right)$. And the simulation results show that the impedance bandwidth of the dual-antenna system is $4.05-5 \mathrm{GHz}(950 \mathrm{MHz})$, with a relative bandwidth of $21 \%$, and the total efficiency within the operating frequency range is ${4 3 \% - 7 8 \%}$, with an antenna element isolation of 15.3 dB.