基于阻抗表面加载的小型化全向高增益天线

Miniaturized Omnidirectional High-gain Antenna with Impedance Surface Loading

提出了一种基于阻抗表面加载的紧凑型水平极化全向高增益腔体天线。通过在由5个腔体级联构成的全向天线中央加载深度可调的梳状阻抗表面,可在宽带频率范围内降低天线的谐振频率,即实现天线的小型化。该梳状阻抗表面是由一维周期性亚波长金属线阵列构成,可等效为在天线辐射口径均匀加载的并联电容。仿真结果表明,通过调节阻抗表面的插入深度,天线的尺寸可缩小42.3%。同时,该天线可在整个调节范围内(频率比1∶1.7)保持良好的全向辐射特性(不圆度小于2.5 dB)、阻抗匹配特性(|S_(11)|]<-10 dB)及最大增益为6.8~8.5 dBi,可应用于体积受限的全向无线通信系统。

A compact horizontally-polarized omnidirectional high-gain cavity antenna is proposed based on impedance surface loading.By loading a comb-shaped impedance surface with adjustable depth in the center of an omnidirectional antenna composed of five cascaded cavities,the antenna resonant frequency can be tuned in a wide frequency range,i.e.,the antenna can be significantly miniaturized.The loaded impedance surface is composed of a one-dimensional periodic sub-wavelength metal line array,which can be equivalent to a parallel capacitor uniformly loaded on the antenna radiation aperture.Simulated results show that by adjusting the insertion depth of the impedance surface,the size of the proposed antenna can be reduced by 42.3%.Meanwhile,the antenna maintains good omnidirectional radiation property(out-of-roundness less than 2.5 dB),impedance matching([|S_(11)|]<-10 dB),and maximum gain of around 6.8~8.5 dBi in a broadband range(frequency ratio up to 1∶1.7),showing great potential usage in volume-limited omnidirectional wireless communication system.