1. Stutzman, W. L. and G. A. Thiele, Antenna Theory and Design, 2nd Edition, Wiley, New York, 1998.
2. Oh, S.-S. and L. Shafai, "Compensated circuit with characteristics of lossless double negative materials and its application to array antennas," IET Microw. Antennas Propag., Vol. 1, No. 1, 29-38, Feb. 2007.
doi:10.1049/iet-map:20050229
3. Mirzaei, H. and G. V. Eleftheriades, "Arbitrary-angle squint-free beamforming in series-fed antenna arrays using non-Foster elements synthesized by negative-group-delay networks," IEEE Trans. Antennas Propag., Vol. 63, No. 5, 1997-2010, May 2015.
doi:10.1109/TAP.2015.2408364
4. Zhu, M. and C.-T. M. Wu, "Negative group delay enabled artificial transmission line exhibiting squint-free, dominant mode, backward leakywave radiation," IEEE MTT-S Int. Microw. Symp. Dig., 309-312, Los Angeles, CA, USA, Aug. 2020.
5. Zhu, M. and C.-T. M.Wu, "Reconfigurable series feed network for squint-free antenna beamforming using distributed amplifier-based negative group delay circuit," Proc. 49th Eur. Microw. Conf. (EuMC), 256-259, Paris, France, Oct. 2019.
6. Zhu, M. and C.-T. M. Wu, "Reconfigurable non-Foster elements and squint-free beamforming networks using active transversal filter-based negative group delay circuit," IEEE Trans. Microw. Theory Techn., Vol. 70, No. 1, 222-231, Jan. 2022.
doi:10.1109/TMTT.2021.3074577
7. Fonseca, N. J. G., A. Ali, and H. Aubert, "Cancellation of beam squint with frequency in serial beamforming network-fed linear array antennas," IEEE Antennas Propag. Mag., Vol. 54, No. 1, 32-39, Feb. 2012.
doi:10.1109/MAP.2012.6202510
8. Cai, S. and J. Liu, "A printed wideband squintless traveling-wave antenna," IEEE Antennas Wireless Propag. Lett., Vol. 20, No. 8, 1473-1477, Aug. 2021.
doi:10.1109/LAWP.2021.3087598
9. Mirzaei, H. and G. V. Eleftheriades, "Eliminating beam-deterioration in wideband linear series-fed antenna arrays using feed networks constructed by slow-wave transmission lines," IEEE Antennas Wireless Propag. Lett., Vol. 15, 798-801, 2016.
doi:10.1109/LAWP.2015.2475279
10. Loecker, C., C. G. Salzburg, K. Herbertz, and T. Bertuch, "Series feeding network based on metamaterial compensation lines," IEEE J. Multiscale Multiphys. Comput. Techn., Vol. 2, 142-146, 2017.
doi:10.1109/JMMCT.2017.2756082
11. Lai, A., K. M. K. H. Leong, and T. Itoh, "Novel series divider for antenna arrays with arbitrary element spacing based on a composite right/left-handed transmission line," Proc. 2005 Eur. Microw. Conf. (EuMC), 145-148, Paris, France, Oct. 2005.
12. Bemani, M. and S. Nikmehr, "Dual-band N-way series power divider using CRLH-TL metamaterials with application in feeding dual-band linear broadside array antenna with reduced beam deterioration," IEEE Trans. Circuits Syst. I, Reg. Papers, Vol. 60, No. 12, 3239-3246, Dec. 2013.
doi:10.1109/TCSI.2013.2255631
13. Ueda, T., S. Yamamoto, Y. Kado, and T. Itoh, "Pseudo-traveling-wave resonator with magnetically tunable phase gradient of fields and its applications to beam-steering antennas," IEEE Trans. Microw. Theory Techn., Vol. 60, No. 10, 3043-3054, Oct. 2012.
doi:10.1109/TMTT.2012.2207737
14. Ueda, T., Y. Kubo, T. Kaneda, M. Hara, Y. Takahashi, and T. Itoh, "Dispersion-free and tunable nonreciprocities in composite right-/left-handed metamaterials and their applications to beam squint reduction in leaky-wave antennas," IEEE Trans. Microw. Theory Techn., Vol. 67, No. 6, 2227-2237, Jun. 2019.
doi:10.1109/TMTT.2019.2909022
15. Eleftheriades, G. V., M. A. Antoniades, and F. Qureshi, "Antenna applications of negativerefractive- index transmission-line structures," IET Microw. Antennas Propag., Vol. 1, No. 1, 12-22, Feb. 2007.
doi:10.1049/iet-map:20050345
16. Antoniades, M. A. and G. V. Eleftheriades, "A CPS leaky-wave antenna with reduced beam deterioration using NRI-TL metamaterials," IEEE Trans. Antennas Propag., Vol. 56, No. 3, 708-721, Mar. 2008.
doi:10.1109/TAP.2008.916965
17. Kossifos, K. M. and M. A. Antoniades, "A NRI-TL metamaterial leaky-wave antenna radiating at broadside with zero beam-deterioration," IEEE Antennas Wireless Propag. Lett., Vol. 17, No. 12, 2223-2227, Dec. 2018.
doi:10.1109/LAWP.2018.2871722
18. Li, H., X. Guo, T. Yu, L. Zhu, and W. Wu, "Wideband continuously tunable phase shifter with phase slope tunability and low phase error," IEEE Trans. Microw. Theory Techn., Vol. 70, No. 4, 2147-2155, Apr. 2022.
doi:10.1109/TMTT.2022.3148429
19. Wi, S.-H., Y.-S. Lee, and J.-G. Yook, "Wideband microstrip patch antenna with U-shaped parasitic elements," IEEE Trans. Antennas Propag., Vol. 55, No. 4, 1196-1199, Apr. 2007.
doi:10.1109/TAP.2007.893427