[1] Pantoli L, Stornelli V and Leuzzi G, Electronics Letters 52, 86 (2015).

[2] Safari M, Shafai C and Shafai L, IEEE Transactions on Antennas and Propagation 63, 1014 (2015).

[3] Guo J, Wu K, XiaoY C, Dong W, Zhang X D, Liu C X and Chen W Y, Journal of Optoelectronics·Laser 26, 1274 (2015). (in Chinese)

[4] Wang Q, Shen Y Y, Xu E M and Li P L, Journal of Optoelectronics ·Laser 26, 1248 (2015). (in Chinese)

[5] Tong Z R, Yang H and Cao Y, Optoelectronics Letters 12, 264 (2016).

[6] Zhao Y J, Jiang B, Li B Y and Wang D H, Optoelectronics Letters 12, 273 (2016).

[7] Zhang J J, Gao L and Yao J P, IEEE Photonics Technology Letters 26, 326 (2014).

[8] Zhao Y J, Zhang R, Wang D H, Zhou B C and Jiang B, Materials Review 26, 167 (2015). (in Chinese)

[9] Li J Q, Xiao Y C, Dong W and Zhang X D, Optoelectronics Letter 12, 276 (2016).

[10] Aghanejad I, Abiri H and Yahaghi A, IEEE Transactions on Antennas and Propagation 60, 4074 (2012).

[11] Rudolph S M and Grbic A, IEEE Transactions on Antennas and Propagation 60, 3661 (2012).

[12] Carignan L P, Yelon A and Menard D, IEEE Transactions on Microwave Theory and Techniques 59, 2568 (2011).

[13] Zou Y P, Technology Innovation and Application 3, 125 (2016). (in Chinese)

[14] Ali K Gorur, Ceyhun Karpuz, Ahmet Ozek and Murat Emur, Microwave and Optical Technology Letters 56, 2211 (2014).

[15] Liu H W, Lei J H, Zhan X, Guan X H, Ji L Y and Ma Z W, Applied Physics Letters 104, 222602 (2014).

[16] Vaishali R, Seema A and Animesh B, Microwave and Optical Technology Letters 57,1222 (2015).