A novel gain/bandwidth enhanced leaky-wave microstrip line antenna with circular polarisation (CP) is proposed. Different from common leaky-wave antennas with an open, short or resistive termination, this antenna consists of a leaky-wave rampart-line antenna terminated with a CP patch radiator. The energy from the feeding point is first radiated by the rampart-line antenna, while the remaining part is radiated through the CP patch element. As a result, the size of the leaky-wave part can be reduced. The resulting size of this antenna is only 1.6 × 1.6 λ _2.4G (λ _2.4G is free space wavelength at 2.4 GHz). Energy loss caused by the resistive termination is avoided, so that high efficiency is achieved – higher than 85% within the whole band. By introducing slight CP centre frequency difference between the patch and rampart antenna, two CP resonances were generated and the 3 dB axial ratio (AR) bandwidth is substantially broadened. Measured AR bandwidth is 9.9% (2.30–2.54 GHz). Its − 10 dB impedance bandwidth is 2.25 GHz to higher than 3 GHz, and peak gain is 13.2 dBic. The proposed antenna has a fully used radiation aperture, achieving a favourable performance, such as wide bandwidth, high gain, and a relatively stable (less tilted) boresight radiation.

中文翻译：

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圆极化微带线漏波天线，贴片端接

提出了一种新型的增益/带宽增强的圆极化泄漏微波微带线天线。与常见的带有开放式，短路式或电阻式终端的泄漏波天线不同，该天线由泄漏波垒线天线和CP贴片辐射器组成。来自馈电点的能量首先由城墙天线辐射，而其余部分则通过CP贴片元件辐射。结果，可以减小漏波部分的尺寸。该天线的最终尺寸仅为1.6× _1.6λ2.4G（ _λ2.4G是2.4 GHz的自由空间波长）。避免了由电阻端接引起的能量损失，从而实现了高效率-在整个频带内高于85％。通过在贴片天线和垒式天线之间引入很小的CP中心频率差，就产生了两个CP谐振，并且3 dB的轴向比率（AR）带宽大大拓宽了。测得的AR带宽为9.9％（2.30–2.54 GHz）。其− 10 dB的阻抗带宽为2.25 GHz至高于3 GHz，峰值增益为13.2 dBic。所提出的天线具有充分使用的辐射孔径，实现了良好的性能，例如宽带宽，高增益和相对稳定（倾斜度较小）的视轴辐射。