In this letter, a symmetrical periodic leaky-wave antenna is proposed using an annular-elliptical-shaped unit cell loaded with balanced shorting pins across the E-plane. The proposed structure is a series-fed antenna array with a microstrip feed-line. The even symmetry field distribution across the longitudinal plane of the unit cell has the controllable propagation constant feature. With excitation of double symmetry (even TM21) mode of an annular elliptical patch at broadside frequency, the open stopband is suppressed. Thus, the antenna shows a wideband and a wide scanning capability of 105° (−78° to 27°). The measured results validate the proposed antenna with a maximum realized gain of 16 dB. The possibility of independent control of the directivity and the main beam direction is also presented at a fixed frequency by simultaneously varying two geometrical parameters.

中文翻译：

---

一种前后向扫描对称周期漏波天线

在这封信中，提出了一种对称的周期性漏波天线，该天线使用环形椭圆形单元，在 E 平面上加载平衡短路引脚。所提出的结构是具有微带馈线的串联馈电天线阵列。跨晶胞纵向平面的均匀对称场分布具有可控的传播常数特征。通过在宽边频率处激发环形椭圆贴片的双对称（甚至 TM21）模式，抑制了开放阻带。因此，天线显示出宽带和 105°（-78° 至 27°）的宽扫描能力。测量结果验证了建议的天线，最大实现增益为 16 dB。