A Miniaturized Dual-Band Dual-Polarized Filtering SISL Antenna for 5G Base Station

A miniaturized dual-band dual-polarized filtering antenna based on substrate-integrated suspended line (SISL) is proposed. For miniaturization, the fundamental mode of the driven patch corresponds to the high band. A new radiation null and resonance point are generated in the lower band after the U-horizontal slot is etched on the driven patch for further miniaturization. Two new radiation nulls and two new resonance points are generated by adding three stacked patches, including the original radiation null of the driven patch, so that four radiation nulls outside the two operating bands can improve the suppression level of out-of-band gain and obtain dual-band filtering performance. The size of the antenna is 0.49λ
_c
× 0.49λ
_c
× 0.07λ
_c
(λ
_c
is the wavelength corresponding to the center frequency of the higher working band). This antenna is manufactured and tested to achieve ±45° dual-polarization performance and is suitable for 3.26–3.62 GHz and 4.65–5.02 GHz in a 5G base station. The isolation between two differential port pairs is greater than 35 dB.