L/S/C/X四频高隔离共口径微带天线设计

首次设计实现了一款能同时工作在L/S/C/X四个频段的高隔离共口径低剖面微带天线。整体结构通过依次按照频率从低至高的顺序自下而上将4个频段的微带天线堆叠而成，采用同轴探针穿过低频辐射贴片形成过孔给高频天线馈电，同时将低频天线作为其上层高频天线的地，以提高天线指标与性能。其中L/S/C波段的辐射贴片采用在矩形辐射贴片四周添加枝节的方式，更利于阻抗调节；X波段置于最顶层，通过对矩形贴片进行开槽处理，避免了对其它频段的辐射遮挡；通过采用中和线去耦合及正交馈电的方法，最终实现了4个频段内增益分别为6.85，7.48，6.13，6.62 dBi；各端口之间隔离均大于30 dB；天线尺寸为85 mm×85 mm×9.07 mm；通过实物加工，测试与仿真结果吻合良好，验证了设计的有效性和可靠性。

Design of highly isolated common aperture microstrip antenna for L/S/C/X band

For the first time, a highly isolated common aperture low-profile microstrip antenna is designed and realized to work in four frequency bands—L/S/C/X, simultaneously. The overall structure is made by stacking microstrip antennas of four bands from bottom to top according to the order of frequency from low to high, using coaxial probes through the low-frequency radiation patch to form an over-hole to feed the high-frequency antenna and using the lower-frequency antenna as the ground of the higher-frequency one in turn to improve the antenna index and performance. Among them, each radiation patch of L/S/C band adopts the way of adding branches around a rectangular radiation patch, which is conducive to impedance adjustment. The X band radiation patch is placed at the top layer, and by slotting the rectangular patch, the radiation blocking to other bands is avoided. By adopting the method of neutralizing line decoupling and orthogonally feeding, the gain in the four bands is finally realized as 6.85 dBi, 7.48 dBi, 6.13 dBi, and 6.62 dBi respectively. The isolation between each port is greater than 30 dB. The antenna size is 85 mm×85 mm×9.07 mm. By means of the physical processing , the test results and simulation ones match well, which verifies the validity and reliability of the design.