A low-profile broadband folded dipole antenna with high gain is presented in this letter. Folded dipole antenna is utilized to reduce the height of the reflector to 0.1 $\lambda$ , without degrading the impedance bandwidth. Parasitic patches shorted to the reflector are employed to reduce the gain variation of the antenna. The $|S_{11}|$ $\leq$ $-$ 10 dB bandwidth of the antenna is from 1.18 to 4.08 GHz (110 $\%$ ) with a broadside gain of 9.25 $\pm$ 1.25 dBi over the bandwidth of 1.27–4.03 GHz (103.8 $\%$ ). The radiation pattern variation of the antenna is small over the bandwidth. The cross-polar level is below $-$ 25 dB from 1.18 to 3.4 GHz. The dimensions of the antenna are 0.78 $\lambda$ × 0.78 $\lambda$ × 0.10 $\lambda$ , where $\lambda$ corresponds to the lowest frequency.

中文翻译：

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薄型宽带高增益折叠偶极天线

这封信中介绍了一种具有高增益的低剖面宽带折叠偶极子天线。利用折叠偶极子天线将反射器的高度降低到0.1 $\lambda$ ，而不会降低阻抗带宽。采用与反射器短路的寄生贴片来减少天线的增益变化。这$|S_{11}|$ $\leq$ $-$ 天线的 10 dB 带宽是从 1.18 到 4.08 GHz (110 $\%$ ) 宽边增益为 9.25 $\下午$ 在 1.27–4.03 GHz (103.8 $\%$ ）。天线的辐射方向图在整个带宽范围内的变化很小。跨极水平低于$-$ 从 1.18 到 3.4 GHz 为 25 dB。天线尺寸为0.78 $\lambda$ × 0.78 $\lambda$ × 0.10 $\lambda$ ， 在哪里 $\lambda$ 对应最低频率。