新型宽带高效率平面耦合环天线设计

Design of a novel planar coupling loop antenna with broadband width and high radiation efficiency

小环天线尺寸小,但存在带宽窄和辐射效率低的缺点。设计了一款具有高辐射效率和一定带宽的耦合环天线。该天线为平面结构,使用电小的内环作为辐射单元,容性多边形外环作为耦合单元,通过内外环耦合增加天线辐射电阻,消除阻抗虚部分量,从而扩展了天线带宽,提高了辐射效率。设计和加工制作了一只中心工作频率为1.3 GHz的天线样品,该天线制作于厚度为0.6 mm的PCB(Printed Circuit Board)板上,内/外环尺寸分别仅为0.06λ和0.26λ,其中λ为中心工作频率对应波长。测试表明,该天线VSWR<2的阻抗带宽达到5.7%(1.28~1.355 GHz);具有类全向方向图,中心频点最大增益约1.98 dBi,天线辐射效率达到96%。该天线结构简单,易于加工,具有一定的工程应用价值。

Small loop antennas is small in size,but has a narrow bandwidth and low radiation efficiency.In this work,a novel coupling loop antenna with high radiation efficiency and certain bandwidth was proposed.It has a planar structure,and an electrically small inner loop and a polygonal outer loop was used as the radiating unit and the coupling unit,respectively.The loops were coupled to improve antenna input impedance,thereby expand the antenna bandwidth and improve its radiation efficiency.An antenna prototype with a center working frequency of 1.3 GHz was designed and fabricated on a PCB with the thickness of 0.6 mm.Its inner and outer loops dimensions are only 0.06λand 0.26λ,respectively,whereλis the wavelength at center operating frequency.The measurement results show that the antenna has a VSWR<2 impedance bandwidth of 5.7%(1.28-1.355 GHz),a nearly omnidirectional pattern with a maximum gain about 1.98 dBi,and a high radiation efficiency up to 96%.This antenna has a simple structure and it is easy to process,so it has certain engineering application potential.