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Abstract: A compact multiband patch antenna is designed by using HFSS in this work, which is filled with composite right/left-handed transmission line (CRLH-TL) structures. The simulated results reveal that the operating frequency becomes lower with left-handed(LH) characteristics of the CRLH-TL structures enhanced, which enable antenna physical size reduction to a large extent. The proposed antenna is fabricated on the substrate Rogers R03201 (relative permittivity of 10.2), which has a compact size of 12 mm × 12 mm × 4 mm. Moreover, this antenna exhibits monopole-like radiation pattern at one resonance frequency and patch-like radiation at the other four resonant frequencies. Therefore, the designed antenna is useful for communication systems.
Key words: Multiband antennas, monopole-like radiation, composite right/left handed transmission line (CRLH-TL).
1. Introduction
In order to meet the requirements of compact and versatile wireless communications systems, more compact and multiband antennas are desirable. Conventionally, multiband antennas are implemented by cutting apertures or adding an additional resonator, etc. However, these antennas have similar radiation patterns and the physical sizes are restricted to the half wavelength of operating frequency. In recent, novel antennas with such characteristics have come up by using composite right/left-handed transmission line(CRLH-TL) structures. Different from traditional right-handed (RH) transmission materials, the antennas based on CRLH-TL demonstrate several unique features of antiparallel group and phase velocities [1-2]. According to the CRLH-TL’s nonlinear dispersion relation, the operating frequencies of the antenna can be controlled by the CRLH-TL structure and the number of unit-cells, which enables the antenna physical size reduction [3]. A triband patch antenna using CRLH-TL structures are exhibited [4], which is overlapped by two different substrates with a height of 8 mm, but its gain is too low with a bad impedance match at each operating frequency. A dual-mode microstrip antenna based on CRLH-TL is implemented with a compact structure [5], while the maximum gain is less than 0 dB and the return loss do not attain -10 dB for n = -1 mode, which limits this antenna practical use for communication systems. A metamaterial CRLH zeroth-order (ZOR) circular patch antenna with two operating frequency is designed with good impedance match [6-7], while the non-periodic structure is unable to realize characters of more operating frequencies. In this paper, an antenna having five operating frequency is proposed by using CRLH-TL structure and combining with aperture cutting technique. According to dispersion theory, the lower left-handed(LH) operating frequencies are determined by antenna structure, which can realize size reduction of the
antenna. Moreover, the good impedance match is attained by cutting gaps on the bottom of ground plane. Simulated results show that this antenna works at 1.8, 2.45, 3.5, 5.0 and 6.75 GHz, whose length is 0.0720λat 1.8 GHz and 0.0960λ at 2.4 GHz. The designed antenna is much smaller than traditional patch antenna.
The paper is organized as follows: In section 2, the structure of CRLH-TL antenna designed is introduced. Then, the authors design and optimize the antenna dimension parameters by making use of HFSS in section 3, and the simulated results of the antenna are also given. Finally, the authors draw a conclusion in section 4.
References
[1] A. Lai, C. Caloz, T. Itoh, Composite right/left-handed transmission line metamaterials, IEEE Microwave Magazine 5 (2004) 34-50.
[2] C. Caloz, T. Itoh, Novel microwave devices and structures based on the transmission line approach of meta-materials, in: 2003 IEEE MTT-S International Microwave Symposium Digest, 2003, Vol. 1, pp. 195-198.
[3] R. Yong-Ho, P. Jae-Hyun, K. Seung-Tae, L. Jeong-Hae, T. Heung-Sik, Multi-band antenna using dual composite right/left handed transmission line, in: IEEE APS 2008, pp. 1-4.
[4] W. Chen, H. Bin-Jie, Z. Xiu-Yin, Compact triband patch antenna with large scale of frequency ratio using CRLH-TL structures, IEEE Antennas and Wireless Propagation Letters 9 (2010) 744-747.
[5] J.X. Niu, Dual-band dual-mode patch antenna based on resonant-type metamaterial transmission line, IET Electronics Letters 46 (2010) 266-268.
[6] S. Yoo, S. Kahng, G. Jang, A novel metamaterial CRLH ZOR circular patch antenna capacitively coupled to a circular ring, in: IEEE APS 2011, pp. 1062-1064.
[7] G. Jang, S. Kahng, J. Ju, J. Anguera, J. Choi, A novel metamaterial CRLH ZOR microstrip patch antenna capacitively coupled to a rectangular ring, in: IEEE APS 2010, pp. 1-4.
[8] Z. Cheng, W. Guang-Ming, L. Jian-Gang, Novel zeroth-order resonator antenna based on composite right/left handed (CRLH) transmission line, in: Proceedings of Cross Strait Quad-Regional Radio Science and Wireless Technology Conference, 2011, Vol. 1, pp. 379-381.
[9] F.J. Herraiz-Martinez, V. Gonzalez-Posadas, F. Inigo-Villacorta, D. Segovia-Vargas, Low-cost approach based on an eigenfrequency method to obtain the dispersion diagram in CRLH structures, IEEE Microw. Wireless Compon. Lett. 17 (1) (2007) 13-15.
Key words: Multiband antennas, monopole-like radiation, composite right/left handed transmission line (CRLH-TL).
1. Introduction
In order to meet the requirements of compact and versatile wireless communications systems, more compact and multiband antennas are desirable. Conventionally, multiband antennas are implemented by cutting apertures or adding an additional resonator, etc. However, these antennas have similar radiation patterns and the physical sizes are restricted to the half wavelength of operating frequency. In recent, novel antennas with such characteristics have come up by using composite right/left-handed transmission line(CRLH-TL) structures. Different from traditional right-handed (RH) transmission materials, the antennas based on CRLH-TL demonstrate several unique features of antiparallel group and phase velocities [1-2]. According to the CRLH-TL’s nonlinear dispersion relation, the operating frequencies of the antenna can be controlled by the CRLH-TL structure and the number of unit-cells, which enables the antenna physical size reduction [3]. A triband patch antenna using CRLH-TL structures are exhibited [4], which is overlapped by two different substrates with a height of 8 mm, but its gain is too low with a bad impedance match at each operating frequency. A dual-mode microstrip antenna based on CRLH-TL is implemented with a compact structure [5], while the maximum gain is less than 0 dB and the return loss do not attain -10 dB for n = -1 mode, which limits this antenna practical use for communication systems. A metamaterial CRLH zeroth-order (ZOR) circular patch antenna with two operating frequency is designed with good impedance match [6-7], while the non-periodic structure is unable to realize characters of more operating frequencies. In this paper, an antenna having five operating frequency is proposed by using CRLH-TL structure and combining with aperture cutting technique. According to dispersion theory, the lower left-handed(LH) operating frequencies are determined by antenna structure, which can realize size reduction of the
antenna. Moreover, the good impedance match is attained by cutting gaps on the bottom of ground plane. Simulated results show that this antenna works at 1.8, 2.45, 3.5, 5.0 and 6.75 GHz, whose length is 0.0720λat 1.8 GHz and 0.0960λ at 2.4 GHz. The designed antenna is much smaller than traditional patch antenna.
The paper is organized as follows: In section 2, the structure of CRLH-TL antenna designed is introduced. Then, the authors design and optimize the antenna dimension parameters by making use of HFSS in section 3, and the simulated results of the antenna are also given. Finally, the authors draw a conclusion in section 4.
References
[1] A. Lai, C. Caloz, T. Itoh, Composite right/left-handed transmission line metamaterials, IEEE Microwave Magazine 5 (2004) 34-50.
[2] C. Caloz, T. Itoh, Novel microwave devices and structures based on the transmission line approach of meta-materials, in: 2003 IEEE MTT-S International Microwave Symposium Digest, 2003, Vol. 1, pp. 195-198.
[3] R. Yong-Ho, P. Jae-Hyun, K. Seung-Tae, L. Jeong-Hae, T. Heung-Sik, Multi-band antenna using dual composite right/left handed transmission line, in: IEEE APS 2008, pp. 1-4.
[4] W. Chen, H. Bin-Jie, Z. Xiu-Yin, Compact triband patch antenna with large scale of frequency ratio using CRLH-TL structures, IEEE Antennas and Wireless Propagation Letters 9 (2010) 744-747.
[5] J.X. Niu, Dual-band dual-mode patch antenna based on resonant-type metamaterial transmission line, IET Electronics Letters 46 (2010) 266-268.
[6] S. Yoo, S. Kahng, G. Jang, A novel metamaterial CRLH ZOR circular patch antenna capacitively coupled to a circular ring, in: IEEE APS 2011, pp. 1062-1064.
[7] G. Jang, S. Kahng, J. Ju, J. Anguera, J. Choi, A novel metamaterial CRLH ZOR microstrip patch antenna capacitively coupled to a rectangular ring, in: IEEE APS 2010, pp. 1-4.
[8] Z. Cheng, W. Guang-Ming, L. Jian-Gang, Novel zeroth-order resonator antenna based on composite right/left handed (CRLH) transmission line, in: Proceedings of Cross Strait Quad-Regional Radio Science and Wireless Technology Conference, 2011, Vol. 1, pp. 379-381.
[9] F.J. Herraiz-Martinez, V. Gonzalez-Posadas, F. Inigo-Villacorta, D. Segovia-Vargas, Low-cost approach based on an eigenfrequency method to obtain the dispersion diagram in CRLH structures, IEEE Microw. Wireless Compon. Lett. 17 (1) (2007) 13-15.